Major desktop environments are KDE as you mentioned and Gnome.
Arch wiki is a good resource even if not running arch. You may want to look into their dotfiles page to back up your settings: https://wiki.archlinux.org/title/Dotfiles.
NixOS ended up being my distro of choice for reproducible installs but it has a high learning curve and poor documentation so I wouldn't recommend to start with. That said you can still use Nix on other distros with home manager to manage dotfiles and install non-system apps.
Distros just pick the default things to install. You can always use the package manager to install something else like a better file manager.
A lot of choices are simply subjective so its hard to recommend any one distro. Mint is close to windows, based on Ubuntu and uses Gnome. Ubuntu based on Debian I find to be user friendly. Not used a Fedora based distro in ages but there is also Silverblue I've heard mentioned positively.
Distros like Arch and NixOS are more design your own system setups. Pick what you want. I used arch for a bit, but got annoyed at keeping all my systems in sync. Had a huge wiki of all the tweaks I made. Then scripts to automate some of it. I started looking at automation tooling like ansible when I found nix.
But you're making this point in defense of someone aligning themselves with a group who targets trans, women, and whoever else they can bully not like them for being their true selves... Do you not see the hypocrisy of such a point given the context of the quote?