pacman hasn't supported the --force option since before Garuda has been existence and trying to use it returns an error so are you sure this is the command you used?
First, if you get errors during an update, never reboot without addressing the errors first.
Wait for 30 seconds after the screen appears to be stuck and see if you can access a TTY by pressing ctrl+alt+f3. If you can, login and run sudo pacman -Syu. If there are errors, share them so we can help you resolve them.
This is not clear to me.
A snapshot is normally taken automatically when you start each update process, so I assume this was done also before the one causing your problems.
So why can't you go back to that time (you'll see the date/time in the grub snapshots)?
I'm with @dalto I would update at least once a week at minimum, but even daily updating won't hurt. One thing I like to add is typically when a update won't finish update your mirrors using reflector. If that doesn't work use Timeshift to rollback the system and try the updates again after updating the mirrors. Typically if you're updating regularly and you have issues with the update applying it's usually because one mirror or another acted up and a reattempt usually wroks.