Yep, for some reasons the recommendation engines seem to have become “oh you glanced at this post for 2 second or you watched a single video, this must be exclusively what you want”
I’ve seen it on social media too, notably Facebook.
Worse than that, at times my home page feed has been 5-10% "Here's a video you've already watched all the way through. Want to watch it again?" recommendations. Like YT can see I've watched the video - why are so many videos I've watched being "recommended" for me?
Then HBO did a machine gun fire of price increases so I cancelled.
For the next few weeks every single YouTube recommended video was an HBO show/movie.
If you scroll down on suggested videos after watching something, it is pretty easy to see how it works. Just keep scrolling and eventually it does start to cycle in a loop of only a few unique options.