Hi,
So to update,
My appdata backup (from CA Backup/Restore) was sadly corrupt, trying to restore it threw an error of "unexcepted eof" when unpack the appdata.tar.gz.
I am writing the steps of what I ended up doing so if someone else has the same issue, this could be used to help them.
1. used btrfs --restore into another disk using the amazing guide @JorgeB wrote and mentioned in my previous comment.
2. Disabled cache pool.
3. configured my 2 SSD as two single cache disks with xfs instead of btrfs (I don't see the point of having a mirrored cache pool if a corruption of the fs causes both disks to die, might as well use the storage and dived one cache disks for only appdata, and the other for VM and fast rw of other applications)
4. restored libvirt.img from CA Backup
5. recreated docker.img
6. copied all the appdata files from step 1 using rsync to the reformatted cache disk
7. reinstalled all container apps from "previous apps"
8. tested containers one by one, inspecting logs and functionality.
9. found out the following container apps were corrupted: authelia (postgress error), swag (certificate chain file error), komga (don't remember the error), lazylibrarian (the docker started fine, but logs showed database errors)
10. removed corrupted container apps, and deleted appdata folders for those containers.
11. reinstalled authelia, swag, komg, lazylibrarian.
12. manually reconfigured those containers, luckily all my swag nginx configuration were save on my pc as well.