As title says. Obviously I could setup different virtual machines or spend the time and install all the DEs in one VM if it is even possible without breaking the OS. I'm wondering if there is an already made iso or something that installs all the maintained DEs for trying.
I agree with NixOS as a good choice for this. The most important bit for me is it cleans up really well when you switch. Every other distro I've tried tends to leave a lot of mess behind and a lot of duplicate function apps.
Just be ready to clean out your home, maybe add a new user to test them. I set up KDE then went back to gnome and it broke my cursors somehow... nbd but it's a bit annoying
Can't say I've seen that yet, but it is a good point. Your home directory might still get a little messy. I think the thought of using the config to me a user per-desktop environment you test is problem a good idea.