snapper -c root create-config /
creates the above error cannot create … “already exists”
umount /.snapshots
btrfs subvolume delete /.snapshots
snapper -c root create-config /
mount /dev/mapper/mine-root on /.snapshots type btrfs (rw,relatime,ssd,discard=async,space_cache,subvolid=916,subvol=/@/.snapshots)