You might notice that Kanji is a key to unlocking a lot more vocabularies, and remembering better, especially if you are not so a beginner, and also reading something alongside.
Perhaps also read something with Furigana. Find something of an appropriate level from Natively, or join a thread in Book Clubs.
Lessons aside, I am doing it once per day. Letting it pile until big enough. And not always finishing the Review (with wrap-up button).
Number of lessons per day depends on you, but it’s probably saner to go small batches at a time. Or perhaps see this guide.
There is this stats website.
Although 100% coverage is at Level 51, it is common that people get more confident around Level 20 or something.