In Ubuntu 20.04 LTS and Ubuntu 20.10, I removed snapd following this steps:
sudo systemctl stop snapd && sudo systemctl disable snapd
sudo apt purge snapd
rm -rf ~/snap sudo rm -rf /snap /var/snap /var/lib/snapd /var/cache/snapd /usr/lib/snapd Then, to avoid that other applications may reinstall it (chromium-browser is an example of application that restores snapd even if installed via apt) you can create a file no-snap.pref by issuing:
sudo -H gedit /etc/apt/preferences.d/no-snap.pref
and then copying the following content in it:
Package: snapd Pin: release a=* Pin-Priority: -10