There's some YouTube channel that adds "Official trailer" to their thumbnails and they mean "their official fan made trailer" and it's annoying and misleading. YouTube has a "don't suggest" option on channels but they need a block.
Fan made trailers need like a [Parody] tag or something, imo
They do have a block/hide option but it's pretty obscure and involves going to the channel's page. I'm not sure about mobile, but on desktop it shows up when you click to Report the channel, though reporting isn't required.
Not my jam, but I don't consider them clickbait unless they're being pushed as real trailers to... bait for clicks.
I mostly see them as a hobby other people enjoy. I'm happy they're happy, but it doesn't interest me. The surge of AI generated slop is different; those are clickbait, not fan-made.