In a ideal world you would have three copies of any digital data.
The live data on the computer.
A local live copy nas and some syncing softwear would be good for this (as a Mac user I use time machine for this)
A offsite backup, cloud is great for this. Or you can use a second drive as above and swap them over weekly/monthly offsite (work locker, mates/mums house etc. Any that you store offsite should use encryption for security. And somewhere you will rotate them, if not stick with cloud based backups.
Restores, backups are worth sweet fa if you can’t restore from them when it hits the fan, so you need to do some test restores every month or two to ensure all is as expected.
The first thing I’d do is try and inventory the data and try and get it into a single location and then see which of the existing drives can be put into use as backup drives.
I belive true image will manage both “local” usb backups/sync and cloud backups among others. I’m sure there are other packages but haven’t used them.