Can’t block or hide from Youtube as the algortihm isn’t customisable in any way. Youtube always decides what shows up, and so far they haven’t done any spectrumwide filtering for AI within their algorithm. As long as it makes their investors happy, they don’t care.
TikTok is the same, there is no corporate incentive for it yet to put that in their algorithm.
You’d have to start blocking algorithmic suggestions all togheter using extensions or alternative clients. And then you can shape your feed by only subscribing to creators that you know are against the use of AI. This principle of choosing to only watch a feed of your chosen content is called federation, and it’s something I’d suggest you look into.
DuckDuckGo is exceptional here with their blocking options, with an option to mitigate the AI stuff in image search.
You can even add https://noai.duckduckgo.com/ for no summaries and AI chat button.