I "whitelist" YouTube for my kids by using youtube-dl to scrape the few good channels for them (Lah Lah, Peppa Pig, etc). I pay for YouTube Premium already, and I only scrape from official channels, so I'm not pirating anything but rather directly accessing channels I paid to view, without having to go through YouTube's horrible interface which constantly (and purposely) pushes crap into my kids view that I never asked for.
Other than that, my kids aren't allowed on YouTube. They can watch scraped videos from our NAS or ABC Kids (Australian Gov-Curated kids TV).