I use this, I like it. I have it coupled with a device management platform that enforces it. (ManageEngine Endpoint Central, free up to 25 devices)

You can also self-host the “connected mode” server and is way more flexible than Family Link in regards to app limits. You can even set time limits for individual app activities. So if your kid likes a certain app, but has features you’d prefer they have less or no access at all to and it’s broken into a separate activity you can just add that activity to a stricter limit

If it’s just a domain, you can transfer registrars pretty eaily