Use -B instead.
Sets Advanced Power Management feature. Possible values are between 1 and 255, low values mean more aggressive power management and higher values mean better performance. Values from 1 to 127 permit spin-down, whereas values from 128 to 254 do not. A value of 255 completely disables the feature.)
Drives connected to usb have an unstable connection in my experience, this is very annoying and gets worse with hubs.
RAIDs reduce the time a system is offline and reduce data loss, if a drive fails and you can afford to wait for the new disk and the backup to restore, and have regular backups that ensure no important data gets lost (though remember the data added between backups may be lost) then you don’t need a RAID.
I don’t use RAIDs cause if my disk fails then I can stomach the 2-4 days it takes to buy a new one and restore the backup
Very important: use S.M.A.R.T and a filesystem with checksums to make sure you’re not backing up corrupted data and know to get a new one
For encryption at rest you may want to look at clevis and tang, though you need a server in your home network for this to work. The client (with clevis) then decrypts the disk at boot if it can reach the server (tang). The server can’t decrypt the data without the client secret and the client can’t decrypt it without the server public key.
Don’t know what your server could be though, maybe a router with custom firmware?
You should also look into cloud storage/rclone, that way you can automate your backups more and reduce the need for manual intervention.
I use rclone and restic to automatically backup my servers daily which takes a few seconds most of the time due to them being incremental backups.
You create a (self-signed) CA certificate, put its certificate as the client ca in your web server.
Then you can create certificates using this CA that you distribute to your devices, only devices that have a certificate signed by your CA are allowed to connect.