All the scenarios you mentioned are power-hungry functions. Not surprised that they are consuming more power than charging. Are u charging from a power outlet(with original charger) or a powerbank? For video calls, try changing to a smaller video resolution or bandwidth. As for high-res video recording, there's no solution to that. It's supposed to shut down when the temperature goes too high.
Just one more thing to add. When you are charging your phone, heat is generated. And when you do this together with those power hungry functions you mentioned, even more heat is generated. If you need to charge it, its better to do it after or before those functions. Not at the same time.
