3 total copies of your data, including your original or “production” data
2 different forms of media
1 off-site copy
Proton Drive can be a decent off-site backup, but it would be a good idea to make a separate backup of your data on a different form of media like an external hard drive, just in case Proton Drive goes down, or the data there gets corrupted and you need to restore a known good version.
The common wisdom about backups is the 3-2-1 backup strategy, which recommends:
Proton Drive can be a decent off-site backup, but it would be a good idea to make a separate backup of your data on a different form of media like an external hard drive, just in case Proton Drive goes down, or the data there gets corrupted and you need to restore a known good version.