“How are they going to prove to the courts that election data is being routed to servers overseas as Sidney Powell claims?”
That is rather easy to do. When the sender logs in or connects to the receiver there is a record. On an email it is in the header. Basically, they can trace the IP address.
You are correct. But apparently there is no source to confirm the existence of the servers, who seized them if they exist, and who has control of them now of they were seized. So there is a long way to go to examining the logs. And if they have not been within the control of reliable law enforcement or military entitiess, the data is no longer assured of being uncorrupted anyway.