I picked up my watch from o2, took out the data deal set it all up, when I leave my phone at home and a call comes through I answer talk for a few seconds then get a overheating message it shuts my call of and puts flight mode on, does exactly the same if I try to make a outgoing call, I'm at a total loss as of what to do, I've tried restarting it then resetting it but still the problem persists, I've checked to see if there is any updates for the watch but there is nothing.
It's pretty much every watch. As the watch is searching for a connection in a weak area it begins to overheat. I experienced this for the first time today, 6/06/2022. I have forgotten my phone at home and tried using my watch to call. Within 15 seconds it began to overheat in an indoor environment. It went into airplane mode and emergency only calls. After approximately 10 minutes it cooled off and came off of airplane and emergency only calls. If I tried to use it for a call it once again it's needed that pattern.
I thought that this problem had been fixed by an update. But I had it again yesterday. I had bluetooth headphones, was working out, got a call and after just a couple minutes it went into 'emergency' mode and wouldn't work until it cooled down. Very frustrating that I cannot use the watch as a phone even though it is sold as a LTE call making device.
I have had both the Galaxy Watch 4 Classic and Galaxy Watch 4. They both have this issue. Surprisingly now they can be on the LTE most of the day (before battery dies) without overheating so I guess they fixed that with an update a while back. Calls are still an issue for me though. Seems to range but longest I've been a phone call on the watch over LTE for 20 minutes before it says it overheats but it's almost guaranteed it will. This is a really stupid issue because it seems to just be an limitation with the watches that they don't mention. I've had a Galaxy Watch 3 and 2 Active LTE and they've all had the same issue. I even got the the Watch 3 replaced and the one I received still had the same issue. I never really used the calling too much at all on the previous watches but now I want to use it more since it would make things more convenient for me now. Looks like I'm definitely going to have to start looking into some other Android LTE smart watches or wait for some other good options to show up. I think I'm pretty much done with Samsung Watches after this because of this issue they seem to not want to fix.
I'm from India, I had the same issue and it was driving me nuts. I did a lot of research online, but couldn't find anything useful. All I knew was that it was not a hardware issue because I successfully used it in a different country. So I decided to switch Carriers. In India, we have the option to keep your existing phone number and port to a different carrier. So I switched from Airtel to Jio 4G and it worked. Haven't had a glitch in forever. I suggest you try that. I don't know what is going on technically but I do know it works. If you do go through with it, let me know how it goes.