Cannot setup Comcst Router to work with Dynamic Dns

I use google domains for all my servers and services. I would like to run a small webserver from home, so i wouldn't like to purchase a static IP. I want to setup dyndns, well, google domains does support this quite well, and i thought that our gateway would as well, but i was mistaken.  Google Domains uses the dyndns2 protocol, but the comcast gateway doesn't allow for the user to input a custom service name for the dynamic dns feature it provides. 

I would like to be using the gateway to update my dns, rather than a computer that continually pings my external IP.

it would be less than trivial to add a domains.google.com service provider in the gateway firmware...