If you are unable to find a replacement display, then the next thing to do is to replace the controller and display. You can (and should) buy them as a kit to avoid compatibility issues as stated above.
KT controllers have good documentation and many users have had great success installing them. Rarely are these plug and play though. Some users have to make new connections or alter the connections the existing components have.
Yes, this will void your warranty.
My experience was pretty good, but still a project. I took measurements of my existing controller to be sure it would fit in the frame and checked all my controllers connections. I did lots of research to understand what all the wires meant before I made the purchase to be sure I wasn’t missing anything. I have a ride1up 700 2020. I bought a KT controller and display. I had to repin my throttle JST connector to get that working. If I had molded Julet plugs, I would’ve had to lop the plug off and connect the wires another way. I also ended up replacing my phase wire connectors with an MT60 plug since that was more tidy and can carry more current than the banana plugs that were there.