I don’t have any advice but I need to point out how hilarious that title is out of context

Pyenv! Let the OS have its own version and work on whatever version you want, whenever.

Probably an unpopular opinion on here, but the OS I recommend for grandparents and parents is ChromeOS. It’s so locked down that it’s almost indestructible, and they almost never need any specialized software that you’d use Windows/MacOS for. If you’re savvy enough you can also use Linux on it in a container, which is how I prefer to use it for day to day stuff (in my case, data related workflows).