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.

You could use https://netboot.xyz/ to boot a bunch of Live systems from various distros relatively quickly (depending on your download speed).

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.

therr are utilities to install lots of isos ona live usb, flash distros that use the des that uou wanna try and you can hotswap them

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)

Usually when you have multiple DEs installed, the login manager would let you choose.

Just need to make sure the autologin don’t get in the way of your choice (e.g. select it thru autologin or disable it completely).

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…

Why not install a live disc type image to USB and try out different varieties? Linux Mint offers three live images with Cinnamon, MATE, and XFCE.

I quickly found this article on installing them to USB: https://itsfoss.com/linux-mint-live-usb/

Many popular distributions offer live images so you can try before installation.

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

Not sure about others but in PopOS (and I assume Ubuntu) it’s pretty simple. Probably easy with most distros.

apt install gnome-desktop
apt install kde-standard
apt install xubuntu-desktop
apt install cinnamon-desktop-environment
apt install xfce4 xfce4-goodies
etc.

NixOS or fedora ostree

Gentoo used to have a live CD with almost every DE / WM in it. Not sure if it’s still around though.

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…