I don’t know if this reassures you, but I’ve been self-studying Japanese for almost two years now, and I’m fluent enough to follow maybe 70-80% of the Shield Hero anime without subtitles (granted, it’s because it’s one of my favourites, so I know the story very well), and frankly,
I couldn’t read a single one of these correctly when reading your post, except for 食う. I hadn’t seen any of the rest other than 黒板, which I could understand because I already speak Chinese. Their meanings should be somewhat guessable in context, and I knew all the readings for the individual kanji except for なか for 半 and こく for 黒, but my point is that I hadn’t encountered them yet.
(Perhaps anime doesn't count for much, so to give you a more concrete idea of what I'm able to do in Japanese now, as well as my limits... )
I can read the first three paragraphs of this article on the huge drop in visitor numbers in Japan (https://www3.nhk.or.jp/news/html/20200520/k10012437611000.html) while guessing/knowing the correct readings for maybe all but five kanji, and guessing/knowing the meaning of all but two words. I can’t read extremely fluently though, and I still don’t know if my accent is accurate, even though I once had a half-Japanese girl I didn’t know say 「すごい！アクセントは結構です。」
Anyway, I’m not here to boast. I haven’t taken the JLPT before (although I hope to do the N1 some day), but the point is…
- I don’t believe those words are N5 level, 食う aside, and even then… N5 is usually absolute beginner level, and beginner textbooks all teach 食べる because 食う isn’t as respectful.
- If I haven’t encountered these words and my ignorance isn’t hindering my comprehension of complex Japanese media, then they’re probably not very commonly used.
From what I understand, WaniKani was built on the premise that the vocabulary taught would be useful. If it’s not on WaniKani, then while it’s not useless, it’s probably not that common. In any case, WaniKani’s main goal is teaching kanji, so I think it’s meant to give you the tools to learn more on your own. It doesn’t teach grammar or a huge amount of vocabulary because that’s not what it’s for. Also, there’s apparently no official list of kanji for each JLPT level. I’d generally trust Jisho’s classification, which I believe WK is based on, and so I think your app might be testing you a slightly above N5 level, but what I want to say is that no source can guarantee what will come out on the JLPT. Your best bet is official practice tests. Also, if you search around on WK forums, some people have said MyTest might be a little shady, so I don’t know how reliable it is. Anyway, honestly, all the best. I hope you continue to find way to enrich your Japanese.