I actually still have yet to hit a roadblock in my WK journey! I’ve never used vacation mode, either. I just aggressively plan my daily workload so that my pace is consistent and easy, and get my daily lessons + reviews done no matter what else is going on in my life. If you’re very busy, taking the scenic route might be a good choice for you, too.
It took me about 2.3 years of daily work (I think about 45 minutes each day) to reach level 60, doing about 12 lessons a day (and ~130 reviews) for most of that time.
Honestly, I don’t feel like it was my WK level that made the most difference in me starting to feel like I was making progress. Grammar is more important, I think. For me, the first big milestone was about one year in. I’d reached N5 grammar, was level 30 in WK, and was, uh, reading a whole bunch of native material that was way, way above my level.
The main benefits to having a decently high WK level at that time were: manga without furigana was totally doable (I still ran into quite a few unknown kanji, but not enough to really slow me down, because it was easy to just quickly draw them on the IME pad), and vocab acquisition in general was a lot easier because I knew the vast majority of the kanji in the extra words that I wanted to learn. I stared mining words from native media and adding them to Anki around this point.
So I’d say that while I undoubtedly have learned a whole lot from WK, my experience with it is mostly that it has made it way easier for me to progress through other tools (my textbooks, mining vocab/kanji, etc.), and it is with those other tools that I have really felt my progress more than with WK.
Concerning that manga you want to read, this is something that really depends on the person! Some people find it really motivating to read something they’re very invested in, even if it’s hard, and other people find it very discouraging to read something if the difficulty is too high. I’d say that manga in particular is a lot harder just because lookups are a much bigger pain, and if it’s already hard to read, you might find it too exhausting to look up everything. But if you’re invested enough, you might be able to push past that.
For me personally, I didn’t have a whole lot of luck reading manga in the early stages. I felt like I wasn’t really getting much out of it because there were way too many unknowns and I didn’t really have the time/energy to dig into everything because the process of doing lookups was tedious. But I’m also not overly invested in manga.
What I did have luck with was reading native media that was entirely digital text that I could easily parse with tools like Yomichan and ichi.moe. Because lookups were quick and easy, I was able to get through the text a lot faster and could investigate more of my questions, and that helped counterbalance any frustrations from my low level of skill.
So I’d say the two most important considerations probably are: 1) your level of personal investment/motivation to read that thing in particular, and 2) ease of doing lookups.
I never did Bunpro, so I can’t really speak to that, but honestly I would recommend against adding another SRS if you already have very little spare time. Doing one SRS can be punishing enough, let alone two. To make that work, you would have to be pretty aggressively consistent with doing your reviews every single day, without breaks, because missing one day could easily cause things to snowball.
I’ve gone the traditional route and have learned the vast majority of my grammar from textbooks. So that’s really the only method that I personally can speak to, though there are plenty of folks on this forum who have never touched a textbook and have managed to get quite far with the language. The nice thing about a textbook is that you can do it at your own pace whenever you happen to have time and you won’t create future work for yourself like you do when studying with an SRS.
As others have said, just give it time! You’ll eventually figure them out, especially as you start to learn more words which contain 室 or 所 and get more of a feel for the nuance there.