I understand that sometimes things are not as simple as "contact support". I've done support for a company, and have had my fair share of using it and not succeeding, especially when it comes to games. However, just 2 questions that I'm curious about:
If one of the machines doesn't bug out, have you started using it as the server? Wouldn't that provide a better experience?
The fact that the machine is newer doesn't mean there may not be other issues at hand. Have you run any form of diagnostics on your machine? Checking if RAM is stable, if there are no disk errors, or the typical SFC /scannow and dism commands to stabilize the OS?