I don’t think you want to run on all of those devices. I think you probably only want to run on your machine and your other machine

I don’t think you can tell a Linux from a Unix. Though in general unixes are tidier, there are Linux users with Unix style and habits that will break the style

Don’t worry about long update gaps, that is just their “between basic package changes” updates. They won’t change you between Apache and Nginx (web servers) within a version number, but you get all the updates for everything over that time

Unless you’re running servers you won’t notice the difference between different distributions’ update schedules

Current Windows seems to need to reboot four times to get installed. Linux updates as it installs so it’s just “reboot and eject installation media to start using your new system”