Iphone 12 stuck in DFU mode

Hello. so, 2 months ago my iphone suddenlt stopped working and when i was plugging it to pc, itunes was showing that its in the DFU mode. Since i couldn't figure out how to fix it I reached for repair service and they said that they also could not fix it, so i just switched to my older phone. after a couple of weeks i reached to another repair shop and the guy said that it wasn't just charged and after half an hour of charging he gave me back my working Iphone.After using it for two weeks exact same situation happened again . So what i assume happened was that when my iphone shuts down it permanently goes to DFU mode and i need to wait for battery to drain so i could turn it back on. How can i fix this?