Good you can hear the pump, so now you know the fuse and relay for it are ok. You still can’t know if the pump is actually performing correctly, as with the rest of the fuel system. Without live diagnostics everything you change is mainly based on speculation and guessing. Your best bet is to follow the advice from Nodge’s forth post, and invest in a cheap reader that will give you access to that live data. Then you’ll be able to track down the fault much easier. It will pay for itself immediately in the time and expense it will save with you being able to rule things in or out of being possible causes of the problem. For starters it will indicate if the fuel pressures on both the LP and HP pumps are within spec.
Good luck
Good luck