My reply might be kind of disappointing, but since you noticed that the thread is not providing ideal feedback/answering your burning questions, then you need to move on and try something different. (By the way, having questions like these are GOOD and normal. It means you’re curious, which translates to being motivated to learn more/become better at expressing yourself!)
If you don’t want to pay for a tutor, there are free alternatives like italki’s journal section, HelloTalk, a Discord group (there are a lot of them), asking your questions on HiNative (probably the best/easiest because there is a template), asking on Japanese Language Stack Exchange or other forums/Reddit, getting a penpal, etc.
Please consider biting the bullet and paying for an italki tutor every couple of weeks (their community tutors are significantly more affordable than their licensed teachers, around $6-10 vs $20+ per hour and you have more freedom to talk about whatever topic you want whenever you want, basically making your own study plan). Seriously, I have really bad social anxiety but talking to italki tutors was the best thing to ever happen in my life. When I started learning Japanese many years ago, I was so afraid that I only used a mic and not a webcam because I didn’t want them to know I was sweating and shaking from anxiety/adrenaline. My heart would pound through my chest while trying to act natural for the whole 30 min ~ 1 hour, but as soon as I hung up it would feel like electricity was buzzing through me in a good way, a way that made me feel so excited and happy to be speaking Japanese. Eventually I got used to speaking/stopped being nervous, and that’s part of a reason why I am so grateful to Japanese every day, it changed my life for the better. (Writing some cheat sheet questions like “Can you repeat that?” “How do you say x?” “Can you write that down?” in Japanese helped a lot, too.) Your title says you are afraid of actually using the language, so that’s why I brought this up.
Anyway, back to writing. There are a few ways to confirm if your writing is correct by yourself. If you have a grammar question like the examples you listed, check Google right away (just write “Japanese ので vs から” and you’ll get a ton of results). There are many free grammar guides that probably already answered your questions. Often times, someone has already asked the question on HiNative/Stack Exchange. The reason you are confused about things like ので vs から is because you haven’t learned the rules, haven’t seen enough examples, or haven’t read an explanation that clicked.
Be sure to check a bilingual dictionary (such as weblio) to see example sentences (you can put quotation marks around phrases so the words don’t get broken apart during the search, ex: “なので”,“ですから”, “New Year”, “special day”, etc). If I search for “特別の日” in weblio, I only get 3 results, so that’s a clue that more research is needed to feel confident in the sentence.
There’s a helpful website called Natsume that lets you search for nouns and it tells you the most common particles + verbs to use it with.
If Natsume doesn’t help, you can paste parts of your sentence into Google to check if it’s a phrase that’s actually used. Pay attention to the number of results (is it in the hundred thousands or are there only 1 or 2 pages of results?) and check if any part of your phrase is being used by native speakers at all. (Searching “新年だから” gave me a lot of results and I can see how different people ended their sentence compared to what I want to say.) If you start realizing the sentence you initially wanted to say isn’t very natural, try to brainstorm other words (ex: You could’ve used 祝う or something.)
You can even add 英語 to your search to see if someone asked for help on DMM (here’s an example of an answer/translation).