Chosen Solution
My watch was lost for several months. After I found it was dead. I put it in the charger and after a day the apple logo will show for a short time and go off. It will not hard reboot. Sometime it is warm after charging but won’t turn on. Is there another way to reboot it?
This sounds like something to do with either water damage or a component shorting out due to warmth. Take it to a specialist for apple watches as they are quite tricky to disassemble.
