iphone 7plus cannot recover

I have had an iphone 7plus for about 1.5 years. Worked really well until suddenly went dark and now it displays the apple logo. Then goes dark. Then again apple logo in about 30 min .

I read instructions and used itunes to update-didn't work. Then I tried the recovery via itunes-twice at home and once in apple store with the genius people. It didn't work (every time waited for 30 min or so until it gave me error mssg.) However, the recovery gave me a different error message every time: 9, 4003, and another 4000 or so code I forgot (maybe 4015). I'm kinda out of options it sounds but what if the lightning connector is flaky and the connection to hardware is poor? I'm sure battery is good-it held charge very well. As last resort I'm thinking about replacing the lightning connector:

Anyone has this issue: 3 different error messages in recovery mode and found a fix? Thanks.

[Edited by Moderator]