I interpret this to mean that YouTube will still host your content; and, anyone with the proper YouTube URLs can watch it, right?  You just need an efficient way to promote the YouTube URLs (because, presumably, YouTube has ceased doing so on your behalf).

I would continue to use YouTube for hosting while I still can; and, focus on trying to migrate your following to Nostr.  Maybe create an nPub just for promoting videos - maybe even a whole Nostr client as a gateway to YouTube URLs could be a good project for someone (similar to what nostr:npub1v5ufyh4lkeslgxxcclg8f0hzazhaw7rsrhvfquxzm2fk64c72hps45n0v5 does for podcasts?).  Either way, a potential audience could have easy access to your library without even necessarily having to set up a Nostr profile if they didn't want to (but could if they wanted to receive notifications, make comments, other engagement, etc).

If you can get to the point that Nostr has sufficiently supplemented your reach, then it would be much less painful to eventually abandon YouTube as your host as well (either voluntarily or otherwise).

I think I would be very hesitant to make the move to rely on another centralized alternative - just to be in the position to potentially get rugged again.