I actually have a NAS (well 2, one Synology, one running MediaVault with docker images as well for fun) but I also cloudback up.
For photo's they are backed up directly to Synology AND Crashplan (at the same time), then sync'd from Synology to Amazon Photos.
For my documents sync'd to Crashplan only.
Anything going to crashplan is encrypted locally. Honestly, I've had to restore from CP before and while it's a little pricey now at $10 a month, having UNLIMITED versions is very VERY useful.
Don't fall for cheaper backups, which after a period of time will hard delete anything you've deleted. So not really backups but more of a sync (and yes that's people like Carbonite etc...)