Extending home wifi - MoCA adapter?

Currently, I am using my own modem on the standard Comcast Xfinity TV/Internet set-up (coax > tv box > coax cable > modem/router). The modem is located on the main level of my townhome and is wired to my entertainment system. The signal strength is not the best on the second floor where my home office is, likely due to interference (townhouses with multiple networks). I have tried wifi extenders with some success, but now that I am working from home, the extenders I have tried don't seem to keep up.

I do have coax ports upstairs. I am trying to find out if there is any configuration or set-up in which I can utilize one of them to set up another router upstairs to boost signal strength.

I know Comcast Xfinity will only let me have one modem on my plan, and I would prefer to leave the modem where it currently is located in the house. Is there a way to set up a MoCA adapter to add a wifi network upstairs? Or could I use the MoCA to have wired connections via ethernet cables? 

Any suggestions would be helpful. Just looking for a plan that will work before I start sinking money into this.