

What about 2 mirrored pools of 2 drives each, then back up the main pool to the other with either ZFS snapshots or a tool like Restic.
Ideally you also need an offsite backup of important files too, but that gets you part way to a robust system that can handle corruption or accidental deletions.









Yes mirrors are the fastest to rebuild I believe, it’s also to give you a backup, as any kind of raid or mirror is not a functional backup, it only provides redundancy.
I would not do raid 10 for the same reason of no backup that way.