I have a personally procured cable modem by ARRIS that supports a second IP address when the ISP provides this.
I was just on the phone for 2 hrs 15 minutes with technical support and they sent me a thread to get an answer. I am starting my own thread at the recommendation of the Comcast employee.
Hello again, JT442. We appreciate you creating your own post here within the community. We discussed checking to see if adding an additional IP address is something that is still available in your area. I will continue working with you privately on this, in order to see if it's something we can accomplish.