I’d go with NixOS in impermanence mode coupled with home-manager and a NixOS service that does the backup “cron job” that another poster talked about (just in case).
Even if she somehow managed to brick the system, you could completely restore it within minutes to the EXACT state you left it in using just these three or four Nix tools. Hell, she could even do it herself by rebooting and selecting a previous config at the start screen. All she needs to do is be able to press down and enter.
I used to keep a list of repos to pull onto my NAS in case they someday went closed source. I use “mr” for it. It worked great. I had it on a systemd timer.
https://myrepos.branchable.com/