I'm planning on moving (back) to Linux from Windows, but I'm not sure which desktop environment I want to use. What's the easiest way to try them all out? Just do a bunch of dnf/apt installs? Is there a distro or project out there that makes this easier?
Looking to try out kde, gnome, budgie, cinnamon, xfce, others
VMs are a way, but Live USB sticks are better because you will see how it actually runs on your bare metal machine, and if there see any hardware quirks, without comitting to an install
You can install them all on any distro I believe. I use Arch and installing Plasma is just a single command, same with Gnome and the others. After install you can pick which desktop to use after the graphical login screen loads.
There are some annoyances, like for example if you have both Gnome and Plasma installed, and you type Files to open a file app, you get the Gnome file app even in Plasma since it's named Files. To use the Plasma file app, you have to type Dolphin instead.
Same with settings app, I often open the Gnome settings app instead of the Plasma settings app by mistake since it's called Settings.
But these are not bugs per se, it's just because I'm used to typing something...
You can install them like any other package from dnf/apt and then run them with startX (if its X11) or start them via their name if they are Wayland compositors (all this in the tty, the black screen with just letter outputs)
The last one is from 2017, alas. The current Gentoo GUI ISO only includes KDE and fluxbox ( full package list, just in case someone's really bored and wants a look).
I find sometimes installing a bunch of different DEs can cause weird cross-issues, so I tend to just make VMs to try out new things. I have a bunch of them on an external drive like little specimen jars lol.
Also as a side note, I keep a VM that's as close to my current setup as possible, so if I get the urge to try something weird I can do it there first and see if it breaks anything.
If the only thing you need to do is test out the different DEs, you should be able to just install each one and use something like lightdm to easily switch between them upon logging out.
VM: doesn't give you the "real" experience. Often feels sluggish.
Installation via package manager: really clutters and messes up your system. There are many dependencies, and then you'll have 5 different file managers for example.
Ventoy: the second best option, or the best, if you just wanna take a look at each. If you really want to try the DE for a few days, it isn't suited of course.
Fedora Atomic (immutable variants like Silverblue): there's a project called uBlue, that provides images for all DEs. You can install the vanilla Silverblue, and then rebase to each according image. Your custom installed programs and personal data stay intact, but everything else gets swapped out cleanly. Each rebase would take ~5 minutes and one reboot, but it feels like you reinstalled your OS and changed the flavor.
Well, if you are new to Linux, it is better if you just install new distros to try them, I would go to Arch Linux as it's the cleanest distro, I could install multiple DE without issues, but then it's a bit mess of packages, also it's harder to install, you need to type archinstall and understand their options. I have a desktop and laptop and I always use the laptop for testing, if you copy the ~/.config folder, you can restore all your applications settings (just copy the app settings you are using), ~/.mozilla to restore your browser as you had it before the wipe and some more settings are under ~/.local. I also copy my ~/.zshrc because I have a custom prompt, configs, add-ons, alias...
Maybe it will be best to give up right now and use GNOME. I hate it, but let's be honest most of the time people are running KDE and others will end up with a bunch of GNOME/GTK/libadwaita components and creating a Frankenstein of a system because some specific App depends on said components.
There's no point on running anything else if you'll end up with parts of GNOME and inconsistencies all over the place.