Just saw the “will be blocked after 3 videos” for the first time" (I was only seeing the generic warning so far). Updated filters and it went away.
I recently stumbled upon this post; seems like filing a complaint to said entity is something you can do if you’re in the EU. I haven’t done so yet, but I plan to. The fella over there has even provided the text he’s sent. If what is said is true and it’s indeed illegal for YouTube to show such prompts (and if that entity receives enough complaints), they might be forced to withdraw them (unless they’re using some legal loophole already).