I’m sure my advice isn’t 100% universal as learning needs are a very individual thing, but I think you’re making the right call with WK- and I’d probably suggest staying especially committed to it in the short term. If your goals are reading full sentences (and reading in general) there’s obviously more to it than just knowing vocabulary, but I have definitely found that a strong vocabulary foundation makes it significantly easier to start introducing more complex material.
For example, if you’re wanting to study grammar or immersive content, not having to continually decode the words used in the material lets you better pick out and focus on the grammatical or cultural concepts that make reading especially challenging. It removes a further tug-of-war and adds focus- and it goes a long, long way.
There’s not really a specific sweet spot or objective threshold to it, but in my own experience and what I’ve seen on these forums- if you can reach the mid 20’s to early 30’s, you’ve filled in a pretty significant portion of the common gaps you’d find in reading material. Even I, someone who is definitely behind on my grammar knowledge, was able to sit down and pretty comfortably read the most recent Yotsuba volume not too long ago because I didn’t have to stumble with the vocabulary used terribly often. I still had to make assumptions, pull out a dictionary a few times, and generally read it a bit crudely- but I still picked up on the humor and effectively never felt lost in the process.
The temptation to jump knee-deep into reading ASAP is definitely a real one, and I certainly don’t blame you for feeling it and I think it’s awesome you’ve given it a lot of effort- but as annoying as it is to gather all the wood and heavy it can be to carry it all at once, it makes the eventual bridge-building process a heck of a lot easier in the long run.
If you are struggling with retention in the meantime, I would highly recommend (if you haven’t already) learning how to write the material you’re learning and practicing it at any opportunity you can. Definitely not without some tedium, but if you spend an active amount of time in your brain recognizing and applying stroke orders and all the little nuances, chances are you’re going to also better reinforce your memorization of meanings and readings. Pen on paper goes a long way, and Jisho.org has stroke order diagrams and videos for all their Kanji.
Level 12 is a great milestone, 1/5th of the way through! I hope you are proud of all the work you’ve done and can’t wait to see you keep learning alongside all of us. I’ll let you know if I think of any more advice as these are just off the top of my head, but luckily you’ve stepped into a very kind, fun, and helpful community and I’m sure they’ll beat me to the punch.