A lot of people use Anki, but I tried it and it wasn’t right for me. I used to use the community created flash card decks on Memrise quite a bit!
Torii - SRS learning application for vocabulary is a nice SRS option! I also pick up vocab on grammar resources like LingoDeer or Bunpro.
You can also check out more resources on old threads like Suggestions for Building Vocabulary
I also study vocab using kids manga—I read as much as I can without looking stuff up first, and then on my second read through I look up new words and make a note of words that come up frequently. I add said words to a physical deck of flash cards or a flash card app.
If you’re studying for the JLPT, I like the Nihongo So-Matome books for vocab.
I’ve picked up a few words watching shows like Terrace House too!
I would play around with a few different apps to see what “clicks” for your learning style! I do well with gamification/SRS or picking up new words via repeated exposure. I don’t often study in complete silence—I usually at least have music on if I’m studying passive skills like reading. If I’m practicing speaking or new grammar then I usually keep my surroundings quiet.