Why does my phone didn’t respond when touched?

The phone can still turn on, but after it is turned on and on the homepage, there is no response when it was touched the screen. I have bring it to the technician, they said the touchscreen is fine (already tried to chabge the LCD, but its still not responsive), so there may be a problem with the IC and it must be factory reset. But the technician is not guaranteeing if the factory reset is not working. Maybe in here there is someone who face the same issue as me. Please help 🙏🏻🙏🏻🙏🏻