Here there are three verbs in this part of the sentence, and you’ve translated those into one verb and two nouns. In particular 高め is not 高い the adjective, but 高める the verb.
This doesn’t really seriously affect your understanding of the overall meaning of the text, I think, and you have the right answer to the question.
The Dictionary is definitely not very helpful here. I had a look around at various online resources, and I think my summary would be:
Things I think of as being “central” uses of のに
If you move away from these then acceptability of のに becomes more dubious, which is I think why the Dictionary marks the のに version of the pool sentence with ??. (Note that this doesn’t mean “ungrammatical, no native speaker would accept this”, which the Dictionary marks with *; the question mark notation is a scale of unacceptability from ? to ???. Two question marks presumably means quite a lot of people would say it was wrong but some people would think it was close enough to the “use this for that” idea to be OK with it.)
It would be this:
Should in Japanese
I’m confused.
親は親切な物だ。should…
今回は、相手を信じてみる事だ。should…
仕事に早くいけばいいと思いますよ。should…
痩せたい人は運動をす可きだと思う。should…
I’m having a hard time telling them apart. I’ll research this further but it’s, well, complicated, just venting 
.
Next exercise:
私たちは、いろいろな場面に合わせて服を着替える。We change our clothes to match various places.
For what it’s worth, back when I learned these, I didn’t learn them as “four ways to say should”, but separately, as different sentence patterns, focusing on what kind of things people say with them rather than an English translation label.
PS: nobody writes べき with kanji. I actually thought that was an input method typo at first…
Well, roughly speaking they are indeed basically saying the same thing – “it would be nice if ~”. The differences are in nuance and derive from the differences in usage of the underlying “if” constructs.
You might have already found this bunpro page which ranks them by degree of certainty:
and it notes on another page that the “if A then definitely B as a natural consequence” strong certainty meaning of と means that it can come out as an expression of “I hope” or “I wish”.
ドライブに行きたいなら、運転免許をとればいいです。(取る)
See here, I can’t instinctively pick up that we’re talking about a lowest strength/certainty. If If having a driver license to drive is the lowest strength, I have a hard time wrapping my mind what would count as higher strength.
However, the speaker’s level of certainty about the result being ‘good’ will change slightly, depending on the particle.
-Bunpro
I don’t understand how to parse this mentally is what I’m saying.
生徒は、先生に従う事だ。
So here, I instinctively typed べきだ but I get “use something weaker”. How am I to tell when something ‘weaker’ corresponds to the right answer to use in context? This might come from a place of misunderstanding but it feels very subjective. Sort of like with modals in English.
It implies some sort of moral obligation, or that (A) is the only reasonable course of action.
ーBunpro
Who’s to say it’s not a quote moral obligation to obey your teacher?
I’d argue it certainly applies here. I know plenty of people who would argue that it’s the responsibility of students to listen to their teachers.
This is CHAT GPT’s take on it:
All three sentences use the verb+べきだ.
痩せたい人は運動をす可きだと思う。(する)
For this answer, I therefore wrote: 痩せたい人は運動をするべきだと思う。but I’m getting a wrong answer, saying it’s すべきだ. So I’m confused. Again, Chat GPT:
寝るのに時間がない。夜更かししすぎた。
I don’t have any time (in order) to sleep. I stayed up too late.
Just to make sure, this would be the first one, right？
翻訳（つづく…）
私たちは、いろいろな場面に合わせて服を着替える。We change our clothes to match various places.
たとえばふだんはTシャツにジーンズの人 も、
I don’t understand the purpose of the に there. Chat gpt’s answer is vague too. It says that に can express a combination, a pairing of things? I don’t this に from any of the に in the dictionary.
パーティーのときはスーツやきれいな服を着るのではないだろうか。During parties, (they) probably don’t wear nice clothes like a suit right?
I think this is “when giving advice, soften things”: often you don’t want to say something straight out but instead leave some wiggle room one way or another. (That doesn’t mean you can’t use the other forms for giving advice; though you might soften them another way, e.g. by throwing in an “I think” or something.)
This maggiesensei page has a lot of examples of ways you can use these “conditional plus いい” forms, including cases where the choice of conditional makes a difference and where it doesn’t.
This feels to me like a problem with doing SRS of grammar points – you can have a situation where several phrasings are all fine, but bunpro wants to see one particular choice and so all it can do is give you that kind of nudge if you give it something that’s not the exact word it wants.
Similarly here, this seems like a “bunpro wants exact answers” problem.
Seems like a reasonable way to think of it.
The combination of する and べき is a rare grammatical exception in Japanese, in which two forms are both considered equally correct. Due to this, either するべき, or すべき may be used.
This special case doesn’t apply for other verbs.
You can use に to mean “and”. The Dictionary doesn’t give this an entry of its own, but there is an index entry for it, which points to the discussion of it in the “to 1” “related expressions” section.
On the other end of the sentence, bunpro’s entry for のではないだろうか may be helpful.
Ok, for those who are wondering, that に is actually part of the と entry.
It’s in the notes of と:
as for のではないだろうか：
私たちは、いろいろな場面に合わせて服を着替える。We change our clothes to match various places.
たとえばふだんはTシャツにジーンズの人 も、For example, people who wear jeans and t-shirts
パーティーのときはスーツやきれいな服を着るのではないだろうか。They probably don’t wear nice clothes like a suit right during parties, don’t you agree?
言葉も同じで、It’s the same thing for languages,
それぞれの場面などによって使いわける。A language is used based on each situation/context.
Notice that your translation has produced something that doesn’t logically make sense as a continuation of the line of argument begun in the first sentence. The second sentence is giving an example of the principle stated in the first sentence.
I guess it means that people who wear jeans and t-shirts don’t wear them during parties then (so that it corresponds to the idea in the first sentence). This is what I gather from the context but:パーティーのときはスーツやきれいな服を着るのではないだろうかMy understanding is that this sentence says that it’s the suits and nice clothes which are described by the negative, not the t-shirts and jeans.
This is why I pointed you at the bunpro article for のではないだろうか. Look at the example sentences there and their translations and how the verb positivity/negativity is working there.
私たちは、いろいろな場面に合わせて服を着替える。We change our clothes to match various places.
たとえばふだんはTシャツにジーンズの人 も、For example, people who normally wear jeans and t-shirts
パーティーのときはスーツやきれいな服を着る = affirmative
のではないだろうか = don’t you agree?
Therefore: Don’t you agree that during parties they’ll wear suits and other nice clothes?
言葉も同じで、It’s the same thing for languages,
それぞれの場面などによって使いわける。A language is used based on each situation/context.
たとえば、日本語は、話すときと書くときで文体が違う。For example, in Japenese, spoken Japanese and written Japanese are different.
また、書き言葉の中には「です・ます 体」「だ体」「である体」などの文体がある。 Also, within written language, there are desu, masu, da, de aru.
初級では、話し言葉の日本語を中心に勉強してきた。At the beginner level, I have been focusing on spoken Japanese language.
I’m not sure if the subject is the speaker here…
Would it be accurate to say that, most of the time, when a subject is omitted, it’s because the speaker is omitted? I mean, it seems to me that omitted subjects often up the speaker. I don’t know if it’s always the case but it seems to be the case very often.中級では書き言葉を学ぶことも増えてくる。 At the intermediate level, I have also began to learn written language. 「だ体」 「である体」という文体も知っておけば、If I knew in advance… If I can know in advance…This is 知って+おく but I think おく is in the potential, おけ So it’s probably more like: If I can know in advance right? If I can also know in advance the da and de aru form…Is that it?
文章 が読みやすくなるだろう。
It’s quite common, especially in conversation, because an omitted subject is one that’s already present and obvious from context, and two possible subjects that are present in the context of every spoken conversation are “I” and “you”. In written compositions this trend is
less pronounced, I think. (In particular written texts are more likely to include extended narration of somebody’s actions, where the omitted subject will be “he” or “she”, and most novels don’t have first person narrators or direct asides to the reader so “I” and “you” are less likely to be in play. Conversations tend to be more focused on the participants and spend less time talking about third parties, but the “obvious in context and not ‘I’ or ‘you’” option is always present.)
I suggest you finish the text and answer the question first, since you’re practically at the end, but in this specific case:
I think there are three options, and which you take it as doesn’t affect the meaning of the text all that much
Either “I”, “we” or “you” works
I would go for “you”, because the text doesn’t seem to be much like “a learner of Japanese sharing his own experience” and is more “somebody who knows giving advice to the reader”
I think you should recheck (1) how the ば verb ending works and (2) how verbs in potential form inflect…
あっ
本当に驚いているの
書いたありがとう 
It’s funny because, in my own leisure reading, I looked this grammar point up yesterday, also…
—±–±–±–
I’m still on my work trip.
It got extended because I was struggling to get to a “pausing point”. I still have a lot to do today, but I’m supposed to be driving home. sigh
ば verbs:
So ～たら and ~ば are both suffixes for non-inevitable results (as opposed to と which is used for inevitable results). I had the form mix in my head with the potential.
会う → 会えば
立つ → 立てば
写す → 写せば
割る → 割れば
書く → 書けば
泳ぐ → 泳げば
死ぬ → 死ねば
学ぶ → 学べば
休む → 休めば
So it seems like you shift to the え column and add ば for godan verbs. For ichidan verbs, you replace ～る with ～れば.
So, here:
「だ体」 「である体」という文体も知っておけば、
is just the conditional ば form. I’ll switch to ‘you’ for the pronoun as opposed to ‘I’.
中級では書き言葉を学ぶことも増えてくる。 At the intermediate level, you will also begin to learn written language.
I’ve also changed the past for the present.
「だ体」 「である体」という文体も知っておけば、
If you also learn the written style called the b plain form and the dearu form in advance,
文章 が読みやすくなるだろう。
Reading essays will probably become easy.
Which is right in the following sentences.
1 日本語にはさまざまな文体があり、 場面などによって変えている。
2 中級の日本語では、書き言葉より話し言葉を中心に勉強する。
3 日本語では、書き言葉と話し言葉の文体がよく似ている。
4 日本語の話し言葉には、「です・ます体」「だ体」「である体」の文体がある。
#1 This one is true! Japanese has various styles which depend on the situation. 
#2 That’s not right. At intermediate level, you focus solely on 書き言葉, 話し言葉 is for beginner level. 
#3 Hmm… I don’t recall the text saying they were similar…
#4 No, that’s 書き言葉.
