Replacement USB-C port not working?

Right, so my FP4’s USB-C port broke (the soldering gave up and the connector detached), so I ordered a new one.

I installed it according to the instructions, but the phone’s still not charging. I took it apart and re-assembled the parts many times to no avail. When I plug a cable in (tried two that I know to work), it feels quite loose once plugged in.

I know a faulty replacement part is unlikely but could that be the case?

Apparently I can only attach one image in a post, but I have more if you need to see some.

Looks like you already performed sensible troubleshooting steps. A faulty replacement part is indeed very unlikely, but not impossible. Did you inspect the part from all sides for any visible damage? And if you could some additional pictures of it, that could also be helpful (especially of the “inside” part of the port, where you plug the actual cable in.