Xfinity doesn’t work for zoom or teams

My internet works fine except for using zoom or teams. I work from home but cannot meet with anyone unless I mute myself on the meeting and I call in separately because my connection is never stable and people can only hear every other word I say. Have tried troubleshooting and unplugging the modem dozens of times. My computer and desk are situated directly next to the modem. Do I need to switch to a different internet provider so I can work from home?