1997 Chevy Lumina 3.1 Fuel System Issues

Hello forum, I’ve been monitoring the long and short term fuel trims in search of solving a low gas mileage issue, and I noticed that the long term fuel trim is running extremely rich (~-18%) and the short term fuel trim stayed relatively close to 0% on idle, but became more rich as throttle input increased (between -10% to -20%). Here is a screenshot of my fuel trims at idle.

From there, I decided to monitor my fuel pressure to see if that could be a cause of the poor air/fuel mixture, and I think I am on to something. Here is a video showing the readout of my fuel pressure gauge after shutting my car off. My car’s fuel pressure drops about 10 psi in a minute (from about ~35 psi to ~25 psi) and continues to decrease as time passes.

Here is a video of my fuel pressure gauge while the car is running. During idle, the needle on the gauge is extremely jumpy, and the fuel pressure seems to be low (about 35 psi when I read that it should be from 41-47 psi, correct me if I’m wrong). I then proceed to give the engine short blips of the throttle and hold it at a constant higher rpm. I then proceed to take the vacuum line off the fuel pressure regulator, and observed an increase in fuel pressure. The line had vacuum, and I didn’t observe any fuel in it. I think I did smell fuel, but it could have been fuel that was on my hands.

My question is that with all the info leading me to believe that there is a problem with the fuel system, what component could be failing in it? I already have replaced my fuel filter, and I have also noticed that my fuel level tends to be inaccurate.
Could it be the fuel pump, fuel pressure regulator, fuel injectors, etc?
Thank you for taking the time to read through my post.