Charger port works when part is tested, but not when in the phone?

I just bought an iphone7 to repair and I am a little confused by what this one is doing.

When I received the phone it was stuck in a boot loop and wouldn’t recognise the charger. I disassembled the phone and plugged in only the screen, the charge port and the battery to test it. It booted OK into setup, the phone was charging fine, and it was recognised by iTunes.

I have put it all back together and now the charger doesn’t work again and iTunes doesn’t see the phone.

Setup process works fine until it gets to the Data & Privacy setting and then it hangs.

Will replacing the charger assembly likely help?

Have I mangled something putting it back together?

Has anyone else had this problem?

thanks for your help.