There are always a lot of risk factors so you can not avoid them or control them completely. By having proper and careful practice, you are only reducing risk but remember that you won't be able to eliminate them entirely.

So my answer is you can not be sure about risk-free with any wallet backup methods. You can see that your backup must be safe (no damages so that it won't become unusable) but when you make multiple backups, you have to save it in different places. It raises risk of one of your backup is accessed by someone else and your Bitcoin wallet will be recovered from that backup, then that person can steal your bitcoin.

To sum up, make multiple backups with some different backup methods, and store all your backups safely.