My guess is it would be the charging port daughter board.
https://www.eddogo.com/for-one-plus-oneplus-5-a5000-usb-charging-port-dock-connector-flex-cable_p1365.html
Is it the charging port assembly or the connector on the logic board broken?
If it's the connector on the logic board broken you will need to take it to someone that does micro-soldering to replace the part, they most likely will have to order a replacement FPC connector for that too.