What Linux build would you recommend that I can fire and forget, that would be compatible with the Windows 10 machine they have running and will likely never replace.
KDE is generally considered close to a Windows experience, although, I'm afraid the "start" menu is still affixed to the left hand side and not in the middle of the taskbar (which is weird). It also doesn't bother with too much telemetry and all that stuff.
Kubuntu is Ubuntu but with the KDE front end, instead of the Gnome one or whatever it is. Being Ubuntu it supports Secure Boot which ticks a box.
It is just as easy to install as any other mainstream Linux distro, which is very easy. Its also quite easy to upgrade. I do recommend that you stick to Long Term Supported (LTS) releases.
I took a customer's "redundant" laptop (destined for land fill, too old, ran slow for Win10) about five years ago and repurposed it for my grand-daughter and stuck Kubuntu on it. If you recall we were heading into Covid related lockdown back then and this was for her to access school remotely.
She is still using it! I have updated it from 18.04 to 24.04 remotely through an OpenVPN tunnel. Try doing that with Windows ...
You should revel in the fact that you now have choice and not a single option. That does mean you will have to pick one.
All of the options you have been presented with will work fine - there is literally no wrong answer here!
All of them are very well documented and you will not get a "SFC /SCANNOW" type answer if you have a problem.
You can center the taskbar. Add a spacer on the left of "Application Launcher" and on the right of "Icons-Only Task Manager", and they'll center what's in between.
Unfortunately, that doesn't completely center the application launcher popup, it's still a bit more on the left. Good enough for me.
However, for folks who don't want to install some random packages, maybe Atomic version of the distro is better: https://fedoraproject.org/atomic-desktops/kinoite/
Atomic Linux desktops has the neat feature for ability to "rollback" if installation fails. A lot like with ChromeOS, the updates are done in atomic fashion and the flipped over to new version.
Normal Linux distributions are more mutable, atomic are lot more immutable.
Fedora's release cycle is usually a little over a year from final release to EOL, at which point, you need to upgrade. My Mom and Dad ain't gonna wanna do that. For them, better to install the latest Ubuntu LTS once, and then I can upgrade for them at Christmas in 4 years.
Fedora is usually a bit...evangelical about open source software. If one of the things you really want is closed source, you'll have to take a few extra steps. Notably Nvidia drivers, but also stuff like Discord or Steam.
Fedora tends to move fast and break things. They tend to adopt things before they're good and ready. I believe Fedora was the first to switch to Wayland, and they did so before it was really ready, but I might be mistaken.
For a lot of users, #1 and #3 above are good things; they want the latest and greatest stuff, but don't want the occasional breakages that result from using a rolling release distro like Arch or Gentoo. For a lot of users, notably my Mom and Dad, they don't want to deal with shit like that, they just want to turn their computer on and forward funny pictures to me and their friends and do their word puzzles.
Fedora is a great distro, and it's the perfect distro for a lot of people, but some of its core philosophical principles make it a suboptimal distro for the less computer literate.
As someone that is 100% on Linux and is occasionally forced to use Teams (where a fat client is no longer possible and was worse than the browser version when it was), I'm curious what that 5% was for you.
I went with Popos. It is simpler than KDE for someone with dexterity and mild cognitive issues. Plus it fixes a lot of the annoying ubuntu / gnome decisions like snaps and hiding the taskbar etc.
There were a few initial teething questions in the first week, but 6 months in now and no other issues (apart from forgetting her password). Highly recommend.
I think it’s pretty good for non dev users. The distro doesn’t provide any earth shattering new innovations but they spend efforts to polish the interface and make it easy to use.
Its pretty good for people who just want a working system and don’t care about whether it’s linux or something else.