So there’s a storage protocol called “S3” (I wanna say it stands for simple scalable storage?), first created by Amazon for AWS. Many types of software, including backup programs, have been designed to use it as a storage backend. There are now many S3 compatible providers as well, last I looked the best value was backblaze B2.

You need a backup program with end-to-end encryption, S3 compatibility, and whatever other features you like. I use restic but it’s CLI only, there’s also borg backup and many others.

If you encrypt locally with a good key, you don’t have to trust the remote storage provider. They just see a bunch of meaningless noise. Just don’t lose the key or your backup is useless.