Minecraft Java Edition
In the afternoon I bought the Minecraft Java Edition as a small Christmas present for our children. I was expecting to be able to install it in my account on the Mac mini and each child be able to run his/her own version. But alas, after I had installed it and we switched to Adam's account starting Minecraft resulted in a small window stating that the Minecraft Launcher was unable to start Minecraft...
Installing Minecraft using my Microsoft account in Adam's session worked, though. So after about an hour of installing, updating, etc. he was finally able to play Minecraft.
I will look further into this issue later.