Got a new box today and lo and behold it’s working just fine! After 10 hours of chat and plugging stuff in, switching connections, etc, they finally agreed to give me a new box! I refused to do any more troubleshooting for them. If they refused to do this I was going to cancel my service.
Thought that was the problem, glad you got it resolved. Support always tries to fix an issue without returning the boxes first, then if nothing works they suggest replacing the box.