98 pathy fuel gauge problem

Hello everyone, new here. I recently bought a 98 pathfinder that's had work done. What I'm concerned about is the fuel gauge barely moving from around the half mark. The fuel pump was replaced by the (buy here pay here) dealer. Fuses under the hood are good and all other gauges work fine. I've done research and it seams this is a typical problem for many year models of pathys. What I would like to know is;

1. Is there anything else I can do to get the fuel gauge to work properly?

2. Is there a hatch in the rear, under the carpet in my 98, like in earlier year model pathys that will keep me from dropping the tank?

I am sure that I will probably have to replace a fuel sending unit/level sensor, but I would like to try all else or at least find the easiest way. Thanks all in advance

I just recently had to put in a fuel pump in a sentra. All I had to do was pull some tabs under the seat and the seat came loose. Hopefully your pathfinder works out easy too, but if not it's not too big a deal to drop a tank if you have a couple people helping(depending on how full the tank is though). Look under the vehicle, see where the tank is exactly, and then try to figure out where all it could be accessed from inside the car. And you may find somewhere that has an access.