NSO Group is not an "Elite Nation State Hacker Group". It's a private Israeli company that sells malware (and apparently malware-as-a-service).

If they didn't rent those servers, it would be very easy for them to say to the court "we did not rent those servers, our clients did". Notably, they did not say this. Probably because they did rent the servers, and if subpoenaed the hosting provider would produce receipts showing that. And then NSO's lawyers would get disbarred.