snapd is typically completely inactive if it is not actively updating, installing removing or connecting things, it usually does not occupy any system resouces and gets activated via a systemd socket when needed …
you can indeed at all time disable that bit as well with the systemctl command, like any other systemd managed service …
i hope you noted down their state before disabling in case you want to turn them back to their defaults, some of them are only for Ubuntu Core and might cause some chaos when enabling them on a classic installation … (i assume you planned to occasionally re-enable snapd if you do not want to simply uninstall it)