I've tried again, and same result: video call with 2 other people, 80° average and fans at 8000 rpm. Al CPU usage at 20-23%.
Honestly I'm quite disappointed with this particular thing.
Zoom seems to perform better, haven't tried teams yet.
I have an Air base. With MS Teams the CPU package jumps around somewhere between 60 and 80, but the fan stays at around 2600 RPM.