Go into the YouTube app, settings, manage all history, under the history tab hit Delete -> delete all time.
Then go to controls (still in the manage all history dialog box under settings), under YouTube history hit Turn off. It says “pausing…” Hit Pause, and Got it.
It’s been exactly 3 months since I did that. I still watch stuff from my subscriptions and when I search for something I want to watch. There are still recommended videos when you’re watching a video but they are a lot less enticing since they are not personally targeted. I curated my subscriptions so it’s more what I would want to spend time watching instead of reaction videos for instance. My actual time watching YouTube has dropped a lot.