1000mbit (1gig) service: modem has only ONE wired port at 1gb, others are 100mbit. Need different router, but cannot contact tech support

I have 3 devices which need to connect to my Xfinity router. There are 4 ports on the router, but ONLY ONE port (port with orang bar marker) appears to be 1000mbit, others are 100mbit. Even the installer was not aware that this router only has one 1gb port. 

Customer support keeps trying to force me to reset the router (then blocks all calls until 10++++ minutes have passed). How to resolve this with relevant person?