well call me stupid, but I am running POP OS! 22.04 currently and can't quite really understand from their excitement web-page how I would try cosmic without a system re-install?
You can just install cosmic, and then switch from gnome to cosmic. Or you can use the cosmic apps under gnome as well. The instructions are in the cosmic epoch git repo. That will get you pretty close.
You could download and flash the .iso to a usb flash drive, then boot from that to try it out (don't choose to install it, if you're given that option)