There's no more unlimited. Jottacloud openly throttle you (probably you could do 10-20TBs eventually given enough time, but not considerably more) and I think OpenDrive finds reasons to kick you out around 10TBs?
Data Hoarder
We are digital librarians. Among us are represented the various reasons to keep data -- legal requirements, competitive requirements, uncertainty of permanence of cloud services, distaste for transmitting your data externally (e.g. government or corporate espionage), cultural and familial archivists, internet collapse preppers, and people who do it themselves so they're sure it's done right. Everyone has their reasons for curating the data they have decided to keep (either forever or For A Damn Long Time (tm) ). Along the way we have sought out like-minded individuals to exchange strategies, war stories, and cautionary tales of failures.
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).
Contact the providers with your requirements directly and see what they can offer
I believe that Uranium Backup can handle this; just install and use it.
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.