Cm1150v and ax600 internet issues

So I just purchased all this equipment. I activated the modem. Connected to router. First we weren’t getting the speed we pay for. Factory reset everything. It’s fine. Xfinity keeps losing connection to modem. We lose connection or get connection sporadically. Xfinity came out twice. Everything’s fine on their end. It’s all brand new. Our previous modem/router was totally fine. Now what?