1) Use Windows 10 with Kids/Family features 2) Switch my kid to use Edge instead of Chrome/Chromium
Nr 1 allows you to block apps (e.g. Calculator, Chrome, Roblox ...) as well as websites - either completely and/or during specific days/times. There's also "screen time" feature - both for the computer/OS itself, as well as per application.
So you can allow kid to have "unlimited" screen time on week days between 8am and 3pm (during "home" school) while block all apps/games except Edge. Then say in the afternoon allow 2 hours for Minecraft/Roblox/etc. Or not allow any - so when they try to launch it you get email/notification and can allow it for the next 5/15 minutes ... 1/3/8 hours.
Nr 2 is mostly because Chrome doesn't care/use Windows block/filter rules. Luckily Edge is basically Chrome that does honor those rules.