Title. Tried to search, found instructions on how to do it in debian-adjacent distros, but I’m in openSUSE, which doesn’t use dpkg.
I also checked the manpage for zypper and found nothing that seemed the part, though I don’t exclude the possibility that I just failed to read it properly.
If you need to clear up space, you’ll want want to delete old snapshots that snapper took. There’s a good overview in YaST.
If you delete packages, they’ll still be part of the previous snapshot, so won’t actually free up space until all the snapshots in which this package was contained are (auto-)deleted.
The snapshots are incremental, so it’s when big changes happen between snapshots that they take up more space.
Gods I forgot about snapper
In my defence I only started using btrfs in any capacity this year.
No worries, I wouldn’t know this, if I had not been in exactly the same situation, desperately trying to free up space by deleting packages and it just not working. Also, Snapper is easy to forget about, which is really a testament to how good it generally is.