You could PROBABLY get away with a it.
But for data durability I don't recommend it.
You're looking at a hard drive enclosure stuck on your router.
It's generally bad engineering-wise. As you really have no way to MANAGE the setup. And you're always a single drive away from data loss.
If you're looking to get something you can manage and use with a backup solution (network drives get EXPENSIVE to back up FAST), look at an actual NAS device. https://www.amazon.com/Synology-bay-DiskStation-DS218-Diskless/dp/B077PJX8TH
Of you want to save a couple bucks, get the Play version, which isn't as upgradeable. https://www.amazon.com/Synology-Disk-Station-DS218play-Diskless/dp/B076G1G2ZT/
While the person who's experienced both "I've got my data backed up" and "What's in the box? WHAT'S IN THE BOX!!!", I shy away from 2 disk setups. It's still doable.
Synology has a technology called Synology Hybrid RAID. Helps keep you from losing data and makes your setup expandable at a later date. Just by trading up drives.
This makes the function similar to the old Drobos.
Also, as I said, the cost and hassle of dealing with mapping network drives (most backup solutions charge you for CLOUD STORAGE, rather than just backup).
With the Synology setup, you can actually mount your drive setup as a local drive through iSCSI.
Meaning it appears like a local drive to the OS.
So, for an online backup like Backblaze (can't recommend it enough), it simply backs it up like it's another drive in your system.
So with SHR, you can start with a single drive, expand it to two later, and as I said, upgrade it down the road.
And the management interface is web based and fairly straightforward.