I had my /home on a subvolume (great as the sub and super share the same space).
When I wanted to reinstall I naively thought I could format the root super volume and keep /home subvolume -- but this was impossible: I had to format /home as well according to the OpenSUSE Tumbleweed installer.
Major problem for me. I now have separate root (btrfs) and home (ext4) partitions.
That's how subvolumes work; not just on btrfs, but on zfs as well.
The non-footgun way is to have several subvolumes (@root, @boot, @home for btrfs, rpool/ROOT/system_instance and rpool/USERDATA for zfs), and nothing in else in the volume itself. Then, you wipe the system subvolume and create a new one, with new system. Or just keep the old system subvolume and create a new one.
You can do it but it's not a very happy path. Easiest way is probably to map the old home subvolume into a different path and either re-label the subvolumes once you're installed or just copy everything over.
Separate BTRFS root and ext4 home partitions is either the default filesystem layout now if you're not doing FDE or the second recommended one.
I do disk encryption of root and home. Not of boot and swap (the attack needed to steal my data in that scenario is too involved: according to my assessment my data is not that valuable)
When I wanted to reinstall I naively thought I could format the root super volume and keep /home subvolume -- but this was impossible: I had to format /home as well according to the OpenSUSE Tumbleweed installer.
Major problem for me. I now have separate root (btrfs) and home (ext4) partitions.