Are you referring to files in the ~home directory? AFAIK these can only be removed manually. You could also try a minimal installation of wtvr flavor you use. If you are referring to backup configuration then use sudo pacman -Rsun snapd This command can sometimes be dangerous and I recommend making a backup before doing it.
No, I was referring to the directory in / where snapd installs all the snaps. In Ubuntu, apt remove snapd only removes snapd, but all the files that were downloaded for running the snaps are still there. (Removing snap from home is easy).
In Ubuntu, one has to do sudo apt autoremove --purge snapd to remove snapd along with all the snaps and config files installed by snapd. I was looking for a similar command in Manjaro, for both snapd and flatpak.