I use Libretube as my kids’ YouTube app. It uses piped instances to stream the videos, and you can pick the instance that works best for you. I’m wondering if there are any Instances that can be used to totally block all NSFW searches, thumbnails, and videos. Do you know of any other apps, ways, or ideas to make YouTube safer for kids? Let me know in the comments!
As a father myself, I wouldn’t recommend this route. Even YouTube has/had some inappropriate content on their kids app (think of ElsaGate), and they have many employees and automated systems in place.
Your safest bet is to self host and only allow or upload videos you vet yourself. That, or supervised screen time.