Additional IP on a residential connection

Hello, I have a Comcast residential connection and I reached out to multiple support staff. I need a secondary ip address For a second router that I need to run behind my modem. The second router cannot be added, and I can’t use VPN due to what I’ll be running on it and latency

From what I understand the option to add an IP address has been removed a while ago, but if you reach out to the white people you still can add it. 

One technician said that he did it and it’ll take time for it to propagate, but I don’t think he did And I never got billed for it. 

This board is my last hope

edit: I have contacted support multiple times and a couple people said that they can do it and they’re escalating it to layer two in which I never heard back.