A little bit of paranoia is not unhealthy… 
I just use 4TB USB drives, and I have four of them that are strictly backups. None are connected except when I’m adding new files to them, and one is always in my safe deposit box at the bank (rotated every few weeks). Another is in my gun safe, which is rated for 60 minutes fireproof at 1200 degrees.
If I somehow lost all 4 drives simultaneously, I’m pretty sure whatever does it will take me out as well, at which point I no longer care. 