Dose eSIM cause heat problem when signal bad?

There is no reason that using an eSIM instead of a physical SIM should cause a heat problem. An eSIM just consists of the same type of information that would be stored on a physical SIM card.

Maybe phones can get hotter in bad signal areas, when they are working harder to try to communicate with towers. But that would be because of the bad signals, not because the SIM for (whichever carrier provided the bad signals) was in electronic form.

Although not in bad signal area, same thing happened to me here. I’m running dual sim, I used eSIM to call someone, the phone gave me the temperature lockout TWO times while just in a phone call and not doing anything else, and yes you can feel it, the phone is so hot that it hurts my hand by just touching it. And I switched back to my physical sim the overheating problem was fixed.

my hypothesis is because on physical sims it’s transmitting carrier+number info from a locally stored device, while eSIM requires to have frequent contact with the carrier’s cell tower for those infos, that’s why apple also needed extra hardware in the phone for it.