I don’t mind the content they watch on kids YouTube (mostly, streamers can be awful), but the exposure to the algorithm turns them into tiny zombies and led to behavior problems. Even adult brains have trouble navigating the dopamine hits of recommendation algorithms optimized to keep you engaged.
We’ve stuck to a middle ground where they are limited to a certain amount of YouTube per day (but have no time limits for Netflix, games, etc). This has worked well so far