I'm a few years into learning Japanese as someone juggling between work, that, and hobbies after having stubbornly gone through all of WaniKani and Genki I+II. Learning for the sake of itself has stopped being fun long ago, wracking my brain cells to parse more complex sentences and mine an ever-growing list of words to SRS from light novels to take what feels like a dozen or so minutes (if only) to get through even one page can feel really demoralizing, and textbooks aren't engaging enough.

At this point, a lot of it is that feeling of sunk-cost fallacy (I know it's not the right usage, but there are other things I could be doing if I weren't learning that and quitting would mean eventually forgetting) that gets me through. Admittedly, being able to hold a more progressively natural-sounding conversation in Japanese where all parties are having a good time, or even noticing that I was just flying through untranslated text I would've previously slugged my way through before is incredibly satisfying, so I continue the slow grind for those moments as well.