you can still make good use of the usb drive with hyperbackup on synology! i have a backup job set to run nightly but keep the drive disconnected (so something like a powersurge can't take out all the disks at once) and then once a month plug in the drive before i go to sleep then plug it back out the next day. the backup job gracefully fails for the rest of the month when the drive is not plugged in, but basically it just means i don't have to log into the synology just to run the backup job.

i have a second drive with an identical backup job and the drive lives in my sister's house 364 days of the year.

there's still the risk of losing a months worth of files but its a pretty low effort and cheap backup system apart from that