For the spoken language I whole heartedly agree, but as far as reading is concerned, immersion is super hard. Most resource won't have furigana and even with the one that do, it's "down one ear and out the other", I don't particularly learn to read Kanjis this way. Once you've got a base of say the 500 most used kanji, and you're able to recognise patterns (components, composition) of kanjis then it's a different story.

I'd add that WaniKani does go into compound words, whilst it teaches ~2000 kanji it teaches ~8000 words of vocabulary (which can be either a single kanji, a compound word, etc.). However it does not teach kana only words such as りんご.

As for my own case, I'm self studiying with a grammar book + the minna no nihong + wanikani + a weekly tutor in immersion, playing Animal Crossing every now and then in Japanese and trying to read Komi san, as well as preparing for a 6 week trip, which will be my third trip to Japan. It's hard to imagine doing anything more – my wife already thinks I'm doing too much.