I’ve learned like 10-11k words between my website + wanikani. Vanilla’s learned like 14k+ Even Nath learned several thousand on Floflo IIRC, and he started at quite an advanced level. It truly is just a grind to fluency.
I’d abandon the “common word decks” like N3/N2, Core 10k, whatever. Just read a book and learn the words. Different genres and series tend to have similar vocabulary, so as long as you lean towards a particular subject matter you’ll be able to attain an acceptable level of fluency. If you jump genres and mediums constantly, it’s a much harder road. I think having a focus is important and then you can easily branch out later.
20-30 new words a day is a good pace. You can get a couple thousand done a year that way and you can expect to be “pretty good” after a year or two.