Linux

Mint feels modern enough to me yet simple enough for seniors to grasp. I wanted something that could work with their printers immediately, which it did (although I had sure spent several hours getting Wi-Fi and sound to work on one of them, as Mint had kept trying to look for other drivers).

One of my biggest annoyances with Fedora is that you seem to be required to have a mouse to navigate through the full extent of its settings, whereas I think at least a larger chunk of Mint's settings can be navigated by keyboard, at least in my limited experience (even though the actual main users probably wouldn't care). Fedora created a popup, I think during sound-testing, that literally could not be interacted with in any way without a mouse cursor that I could find. This is partly why I'm sticking to Mint Cinnamon for even my own machine, plus issues I had with Bazzite (Steam itself ironically never showing a window and only putting itself in the system tray despite what I tried, etc.).