Minecraft on iPad - want to switch appleid to my sons account but afraid he will lose his progress

I have iPad Air 3, this was shared w my son for the past year under my AppleID. I'd like to hand it over to him entirely - under his own AppleID. I would have him under Family Sharing with my account, I pay for upgraded iCloud storage.

He is concerned that the switch over will have him lose everything hes worked for in-game the past year.

His Minecraft (Microsoft) account is separate from his AppleID. Are all his skins and mods and achievements stored locally on the iPad, iCloud or to his Microsoft account? How best can I switch AppleIDs and still save everything hes worked for?