I highly recommend buying a cheap spinning drive and using that for backups. Like, they’re so cheap there really is no reason not to do that. Here in the US you’ll pay about $70 for 2TB, and you get more for your money as capacity increases (until it gets ridiculously high).
Granted, it seems prices may be a hair higher now than they were before the virus hit, but I really don’t think you’ll find a better solution.
Well, you could also do cloud-backups I suppose.
Either way I would probably use the smaller drive for the OS and software, and the larger drive for project files etc.