@fortsings
Many routers allow for the connection of a USB drive that you can use to store information. Some allow for the USB drive to be a Time Machine Backup for Apple MACs but many do not support the drive type needed. Time Machine Backups to the router are slower than a direct connected USB drive to the computer.
I have a USB drive on my router where I manually store files for both storage and a way to transfer data between devices. I use standalone USB drives for backup each computer as I have multiple drives that I rotate. Having only one backup is not good.
Also you can set up a NAS.