What does it take to get a Technician to actually troubleshoot my issue??

My experience with support has been very frustrating, to say the least. I have been experiencing quite a bit of packet loss and downtime for at least the last month. I start a chat with the Xfinity assistant and go through all the level 1 troubleshooting (which I had already done myself) and got nowhere (prior to this I had already switched back to my old Netgear CM700 modem from the CM1200 I was using and the packet loss/downtime was still prevalent). I started another chat and insisted I speak to a human instead of a bot, and we go through all the same troubleshooting steps the bot did. I insist numerous times that I think the issue is with the cable coming to the house, or some other outside issue. The support person I am chatting with then suggests that I upgrade my service to the unlimited plan and use their xfinity modem.

I fail to understand how this will fix my issue. I've already tried both known good working modems I have and the Internet connection is still not stable. Rather than actually looking into fixing my problem, xfinity just wants to sell me different service. Completely frustrated, I ended the chat as it was obvious the person had no interest in helping me with the actual problem.

So again, what does it take to get an actual technician to come onsite and troubleshoot the problem???