Storage isn’t nearly as expensive as it would seem looking at normal consumer cloud storage pricing. I think they also clear the cache of truly obscure content after a while. And I also think some of the “cached” content isn’t even stored on their own servers, but is actually streamed from one of the 3rd party direct download services. That would ease the storage and traffic load massively.
Ah okay now I understand too.
I like to choose my own country in the VPN, I think it’s the best bet for connection stability. Contract wise I don’t think Real-Debrid cares at all what your IP is, so many people fake it anyway.