I don't know how relevant Elsagate is still, but there was a series of really violent, gory, and outright awful content being uploaded with the guise of it being for kids by featuring popular characters like spiderman or mickey mouse. Honestly there's so much outright garbage on that platform you're better off restricting your kid to content you've already vetted rather than giving them everything but what you've blocked.
Anything educational or that teaches morals would probably be best. I heard good things about Bluey, other than it sometimes puts high expectations on parents to live up to the incredible feats of energy and effort of the parents in the show. Beyond that, maybe some crafts and science experiment channels would be good too. But for the love of god, avoid Cocomelon and toy reviews, that's just asking for brainrot and a parasocial relationship respectively.
(also I'm totally going to be that guy for a moment here who tells you how to raise your kid, but be careful when you let your kid watch. I've seen so many parents let their kids play in the middle of a restaurant, or even in a place of worship, and it's always obnoxious to everyone around them. Even as a kid myself I had to learn how to deal with hour-long periods boredom, even when I had a gameboy with me that would have provided entertainment. I've also got ADD/ADHD which makes it REALLY hard to do, but I'd say it was worth it.)