IDK anything about 3d printing, but is their online service so complicated that people can't create an open source self hosted alternative? If they can already take the LAN version and send spoofed requests to their servers, they can do the same to a new fully open server.

Surely people can check the traffic and build a server to answer similarly, no? Or is this much more than job management?

Maybe this is impossible and I'm talking out of my ass, but for me it seems like a perfect opportunity to completely remove the problematic party from the equation.