Thanks to everyone for their comments. I actually ended up with Pcloud: I took today's Black Friday offer of 10 TB storage for a one time lifetime fee of €890. Unless they go out of business, I expect this will suffice for my needs indefinitely.
Of course I realize that neither are really unlimited. But like I said 10-15 TB should be more than enough. I actually don't expect to cross the 10 TB mark any time soon (definitely not within the next few years).
I noticed about Jottacloud's speed throttling, that actually doesn't seem too problematic for my case. As for OpenDrive, do they actually kick people out that have like 10 TB stored? (which I won't have initially, but may get there eventually).
I'm looking for a cloud backup service that allows me to upload daily backups from my macbook and home Linux server automatically without having to worry about storage limits.
Of course I understand 'unlimited' is never actually unlimited, in my use case I guess I'll typically stay below 10-15 TB for many years to come.
After comparing many alternatives it boils down to OpenDrive or Jottacloud for me. I have tried free trial accounts with both, and they both seem to work OK for my needs. Also the cost is about the same. I don't care about encryption, all my uploaded archives are encrypted client side anyway.
Also I don't need fancy client or backup software, I upload from CLI only (using rclone).
Any user experiences that would recommend either of these, or favor one over the other?
Any insight is much appreciated!