They probably will want to play games. It's a slippery slope. But if you go that route:
Steam works amazingly well. And you can set up family controls.
Roblox works great using "Sober" I don't recommend letting them play Roblox but I'm stuck with it.
Minecraft and Curseforge work well, too.
Time Keeper Next is a great time limiting control system. If you have a little awareness of docker you can run it in a container and even access it on your phone through an admin gui. If you need help on that get my email from my profile and I'll happily share my details.
My kids 8,10,12 know how to use the command line. I'm really proud of them.