WiFi not stable - cuts out randomly

about 2 months ago, my wifi suddenly started cutting out at random times throughout the day. I have had to use the app to troubleshoot as well as speak to agents with no successful resolution. Tech installed a new modem / gateway and it still happens. It’s impossible to work from home given this situation. How does this get fixed??? I have had xfinity WiFi for over 10 years without having this type of problem. There must be some sort of new interference. I can’t keep this service if this is the new normal.