Sounds familiar, my post from 7 months ago:

"I would love to see someone look deep into Twitch recommendation system - last time I tested the thing they call "Feedback" is a rolling buffer and wont let you exclude more than ~100 things, adding more simply removed oldest entries and starts spamming you with things you already excluded in the past. This looked like performance optimization (less things to track per user)."

Why isn't this a variant on a bloom filter that supports deletion? eg vacuum filter

I am convinced the not interested button does absolutely nothing.

I'm baffled by people who says things like this. I make heavy use of both "Not Interested" and "Don't recommend Channel". They don't do as much as I would like (why oh why does Youtube insist on thinking I'm interested in obscure Rap/Hip Hop?), but I can clearly see recommendations shift over time. Marking any single video doesn't seem to do much, but marking 5-10 similar videos (mostly) does something.

Paid promotion (by channels) breaks past the barriers... It's part of the conflict of maintaining the illusion that sponsored content is what gets first placement throughout YouTube.

Its also maddening to content creators how newly upload content lists only feature paid promotional content every time. That's also exactly what makes certain (paid) content look massively popular over everything else, even when the production values are sub-par.

It does at least blacklist that exact video.

The "don't recommend channel" feature works fine for me, but I have probably blocked only a few hundred channels.

I have this exact problem on YouTube and spotify.

this isn't true. I have clicked "no interested" on hundreds of videos and channels. It works

Everyone on platforms now has a different experience because of configuration and account maturity. Invalidating another user's experience because of yours is not helpful to meaningful discussion. I did not downvote you though.