A way to connect my Sensi smart thermostat. Can I add a secondary router?

I'm new to xfinity, it is at my rental property. I bought a Sensi Smart Thermostat to install in my rental so that I can keep an eye on outages, etc. I'm trying to install today and it appears that Xf is not compatible with Copeland/Emerson smart thermostats. I need a 2.4 band as well.  I went ahead and split my bands and name the 2.4 separately, but it still won't connect. Is it possible to get a second router, directly connect it to my Xfin and then try to connect my thermostat?  Help appreciated.