Work with holding power button

Gemibook Plus. I took it apart, disconnected the battery, realized that I couldn’t do anything and put it back together. After that, it either works only when charging, or WHEN THE POWER BUTTON IS PRESSED. I mean WHILE I HOLD THE BUTTON IT WORKS, the battery is normal. I took it to the service, it turned out that I bent one contact, but they straightened it out, but the problem remained. I don’t understand at all how to solve this problem.

Maybe sending it to repair but is possible the hardware is already damaged…