Kindly accept our apologies for what you are facing with your phone, noting that the Video calls are heavy on the phone's performance for sure especially If the customer used to make these calls in daily life. However, you may visit the serivce center for further check If you feel that the case still exists.
Hi, I have the same problem with my new S23 Ultra. I understand Video calls are heavy on a phone, however this should not happen in a phone of this price range. My previous phone was a Hawuai Mate 20 and I did Teams calls all day without this issue at all, and that is a 200€ phone. There is something wrong with Samsung and TEams, you should check it out and release a fix.
