KDE Plasma is the best desktop (or you can choose to be wrong)
and then...
if someone is STRONGLY pushing a specific distro/package manager/whatever? Ignore them.
lol. I love it. :P
To OP though, if you really don't want to "distro-hop", you definitely should test drive several. Look into Ventoy, it basically makes a bootable flash drive that has a separate folder/partition you can just drop bootable .iso files into, and then on boot Ventoy shows you basically a boot menu that lets you pick any one of the images to boot. If you get a nice and big usb flash drive, you can get basically ALL of the distros you want to try on one bootable usb stick so test driving them requires a lot less time and effort. You won't get a good idea of performance typically from a live environment, but you get a very good idea for the "look and feel" which will likely help you narrow it down a lot.
Ummm... Barbarian Unarmored Defense is based off Con, not Dex. They just didn't take away the default Dex bonus to AC that every class in the game gets. They shrug off damage by having a high Con. Barbarians are pretty good as it is, if you let them completely dump Dex and give AC from Str, they would be broken AF... 18 AC at level 1 with a shield under point buy system, and immediate jump to 20 AC at level 4, with no reduction in damage output at all. Possible to be 20 AC at level 1 literally completely naked (no shield) with rolled stats, and 18 isn't even entirely unlikely...