iPhone 7 still on bootloop even after updating the software

Hi. My iPhone started to bootloop after I paused the download for the new software.

I already did simultaneously holding the volume down and on/off button on the side. The support.apple.com/iphone/restore appeared (which I think is the dfu mode). I did what it asked, connected it to my itunes on pc, the "There's a problem with the [your device name] that requires it to be updated or restored." appeared, I updated its software but still on the bootloop.

Also, my iphone kept disconnecting for every 15 mins and tried several cables but still kept disconnecting. I downloaded the software through ipsw, installed the new software but still on the bootloop.

What should I do? Please help. Do you think that I need to approach techs?