I do remember my joy, when finding out that instead of feeding it with batteries, I could even use the power adapter of the master system to play with the Gamegear. 😄
Another +1 for restic. To simplify the backup I am however using https://autorestic.vercel.app/, which is triggered from systemd timers for automated backups.
The first layer in that docker container is actually KVM. So you run the container to run kvm, which then emulates osx.