I would argue either RAID 5 or ZFS RAIDz1 are inherently unsafe, since recovery would take a lot of read-write operations, and you better pray every drive will hold up well even after one clearly failed.

RAID6/ZFS RAIDz2 is the way. Yes, you’re gonna lose a bit more space, but added reliability is priceless.

(And, in any case, make backups for anything critical!)