Hey new member here! Just recently purchased an R50 this week and I had to tackle this exact problem! My fuel level sensor was working correctly as well but I think it's a win/loss no matter what issue you run into. The fuel level sensor looks like an expensive part while the instrument cluster is technical but cheap.
I will say my fuel tank seal did NOT want to go back in place. It had stretched out so much I couldn't fit it back in the grooves. I was looking for the fuel tank seal online and was struggling trying to find one that wasn't outrageous expensive.
There is one on rockauto and I believe I found a cheap part #. The Carter PTS2043. Anyways
I took apart the instrument cluster and you really want to just take everything apart. The LCD screen just pulls straight up. Wiggle it out if you need to. I have always been terrible at soldering, especially electronics but I tried this and I believe I fixed it on the first try. I focused on the resistors you mentioned while also touching up others.
Multiple of my bulbs in the instrument cluster were out. They are the Toshiba v-2. A quick Google search shows that you can pull the bulbs out and replace them with #74 mini bulbs. (2-pack at AutoZone for $6). I ended up grabbing them with pliers and destroying 2 out of the 4 I was replacing. A YouTube video that shows using a thumbtacks to remove the bulb just ended up breaking the plastic holder. I may end up switching to LEDs in the future but this worked out for me since I wanted to complete the project that day.