CM1000/CM1200 Compatibility with Orbi RBR750

I am trying to replace my current modem (C7000v2) due to it constantly dropping connection. I have the broadcasting SSID off seen as I have the C7000v2 hooked up to an RBR750 Orbi (via ethernet of course) along with 2 satellites. I purchased the CM1000 and CM1200, both refurbished on Amazon. I purchased the CM1200 first, but after learning only one ethernet port works at a time or something like that I ordered the CM1000 to save a little bit of money. I tried both modems and called Spectrum to activate them (obviously not at the same time) however they failed to connect to the orbi. I tried factory resetting the orbi and it would get stuck at checking internet connection in the set up process. I tried hooking up my PC directly to the modem to determine if there was any internet connection at all coming from the modems and could confirm there was. I did try using different ethernet cables however they didn't seem to work. Is there something specific I have to do in order to get one of the modems working with the orbi? Or am I stuck replacing the orbi as well? Additionally, I did try spectrums modem and failed to get that connected with the orbi as well.