I gather there’s likely a difference between your use-case and my own, but just to add my two-cents for anyone whose workload lines up. I maintain strictly backup storage, mostly cold as I only ever pull data off of my storage when things catastrophically fail, to the extent I cannot rebuild things from the local copies. I have been using Backblaze’s B2 for a few years now with very few complaints.
It costs $0.005/GB ($5/TB) for the storage, no cost for uploads, $0.01/GB ($10/TB) for downloads. No minimum requirement. It’s S3-compatible, includes most of the usual features like buckets, snapshots, ACLs, etc.–and it’s widely supported among apps and services like Duplicati and rclone.
I understand there are more affordable options out there, I hesitate to adopt most of them due to how frequently I see them fold after a year or two. I have no opinion one way or another about Backblaze as a company or their other services. But for the price, features, and rock-solid stability, I have yet to find anything that would motivate me to try anything other than B2 storage.