Unstable internet

Hello: I had my own router/modem combo, I decided to make my tiny apt smart which failed he is not smart at all, going to the point, after trying with my router/modem and having no success I was told to get the xfinty router... worst than any other, I keep loosing signal and it keep saying unstable internet, I have to unplugged the echo dot, take off the WiFi from 2 phones
Is order for my daughter to have a meeting via zoom, the video chat drop 7 times consecutively, and in all honesty I never experienced that much drop in one day from the internet when I was using my router, I work from home and while I was working today more than 12 times the internet stopped and I lost everything all those times... this is outrageous and is not cheap to pay for an erratic network connection. I have been dealing with this since Saturday called Xfinity more than 20 times since Saturday and no one has resolved this issues!!! I need HELP... thank you