The easiest and maybe even safest way to make a backup is to keep it somewhere online. Just hide it into a crypto container before doing anything.
Where online, there is such a thing as hacking and if hackers trace that your coins are online they will try to hack it, what's the use of hardware wallets if keeping it online is safer and about OP's offer, this is for those who want to keep a huge amount of Bitcoin because it's not cheap.
Man, just read what I wrote and what you actually quoted. You don't need to to upload a .dat file straight to the cloud. Download some software like VeraCrypt, put your keys into the crypto container, set a safe password and don't give a fuck about hackers. You can even upload it to the cloud and post a download link in your twitter. It will take ages to brute force a good password while there is no other way to open a crypto container.