Eh I recently switched to two 14tb disks of different manufacturers. One is usually in standby and once a week I do a rsync to it. Btrfs on both for checksums.

Good enough for me, I assume it's way more likely that a PSU failure fries them all, in which case no variant of raid would have helped anyways. For important stuff I have an off-site Backup, but that's only around 800gb anyways and growing a few gb per year.