Snaps are a nightmare. I've been using a VNC based remote setup for ages for our online training. In the latest ubuntu LTS there's a bug where applications installed via snaps don't trigger the appropriate cgroup permissions when running under VNC so you can't launch any of those applications. The bug is reported, verified and well described but no one from Canonical seems to be interested in applying a fix. I've ended up having to install a browser from the main Firefox site because I literally can't get the snap installed version to run any more.