iMac 21.5 inch, late 2013 with Quad core Intel core i5. Catalina 10.15.7. I am on Satellite ISP, former Wild Blue/ Exede, now Viasat. Things deteriorated to where I could only open in Safe Start, which I used to clear all traces of Teams (hard because it inserts in half a dozen places). I eventually got back to some function. Teams disabled both my audio and video, stating that I needed a Teams compatible version of each. Maddeningly, Teams has become monopoly vendor to both Federal and State government, and I find myself frozen out of meetings I formerly joined with no effort. I can get onto some with telephone connection, but virtually impossible to participate. Teams is Version 1:00.333671.
With my satellite, I have never been able to use Skype, which is a bandwidth hog. I have too slow an uplink to have more than placemaker. I suspect Teams is doing the same to me. Teams is a large application file: 254 MB.