[ghfhghg]

The "don't show this channel" feature also feels like there is some kind of expiry because I've blocked a few channels multiple times now via that method.

Totally a theory but sometimes YouTube has a button that says roughly "show me something new". I think that may be the source of those channels returning.

[vunderba]

Agreed. I've told YT about a thousand times I have zero friggin interest in YouTube Shorts and lo and behold a few weeks later they guiltily try to sneak back into the home page.