Two 4TB Ext USB3 HD's and a Safety Deposit box at your Bank.
Cheap, more or less convenient (get four drives and rotate your backup drives), and secure.
Easier yet if you can pair the amount of crucial stuff to under 4TB, then it's just one drive that you can rotate monthly (weekly?).
Easier yet if you can pair the amount of crucial stuff to under 4TB, then it's just one drive that you can rotate monthly (weekly?).