I hate to sound discouraging here, but you should be aware.

When an engine gets low oil pressure it is quite common and sounds quite natural to blame it on the oil pump. Unless the oil pump is completely broken, replacing it will rarely, if ever bring the oil pressure back up.

When oil pressure is low it is almost always caused by worn engine bearings. When they get too loose the restriction to oil flow decreases and thus the oil pressure decreases.

In this case it is worth checking the gauge by connecting a mechanical gauge temporarily. If the mechanical gauge agrees with the in car gauge then it is time for overhaul or at minimum exploratory surgery.

I hope you're not one to shoot the messenger.

Best of luck,