I was thinking about putting it in an encrypted file and upload it to a host.
Encrypt with good old pgp or pgpi. Perhaps it's to much work thinking about it.
It would give an extra password to remember. For decrypting the file again. And some keys or something.
Put an end to the nonsense with a piece of paper.
Then you might as well as uploading encrypted wallet file (e.g. wallet.dat generated by Bitcoin Core) which also contain TX history, TX label, address label and other data. More information would be backed up, without managing PGP public/private key.