I'm experiencing the same thing. I've got almost 1800 days on my Spanish streak in Duolingo right now, and I speak it decently well [1], but that's only because I knew some Spanish growing up with a multilingual best friend.
Duolingo was pretty good, say, 1500 days ago; I felt like it was really helping me brush up on those forgotten Spanish skills and even helping me learn new things that I didn't know. But it's gone through so much gamification since then that I haven't felt like I've been learning anything in a long, long time. Their primary focus now is to get me to download their AI app and pay a subscription for that, instead of actually teaching me the language I'm learning. And before the AI app, the focus was getting me to purchase DuoBucks (or whatever they are) so I could have more time to race the clock on those impossible timed countdown lessons.
Now I only log in to keep that streak going each day – streaks are one of my primary motivators in other parts of my life so it's hard for me to let this one drop, even though it's not doing much for me.
[1] If I were a young, Spanish-speaking kid.