No sound during calls on iPhone 11 Pro Max after iOS 18 update

I updated my iPhone 11 Pro Max to the iOS 18 and now I have no sound during calls. If I switch to speaker, it is ok, but there is absolutely no sound in my regular speaker (even though for other types of sounds it works just fine - for example if the line is busy, I hear the busy tone). When I try to make a call, when the call connects, I can hear a very short sound (like a sound line closing) and then the ear speaker is completely dead. The volume can be controlled during the call, there is no change regardless the level. I tried to restart it, restore a previous backup, no change. It is surely related to the update, as it worked just fine right before the update and after the update it didn't. It stayed on my desk the entire time, no fall or any other accident.