1) Physical Media that YOU physically own & control.

2) Off-Site Backups

Regardless of the threat, whether it is just bad media, house fire, ordinary thieves, or the FBI, relying on some cloud service as your only backup is a plan to fail.

If it is a threat if someone reads the backups, encrypt.

Sure, as a supplemental convenience, use Google or something. But as the only backup of your life's work? I feel really bad for them, they're obviously gutted. But at the same time, Google has been so publicly unreliable and high-handed for so many years (decades, really), that it's hard not to also feel some, 'whelp, what did you expect, doing something like leaving your valuables out on the sidewalk?'.

Edit: And test your backups