LCD graphics display. Arduino / Raspberry Pi coding

We use a square LCD panel to display our flight simulator instruments with Xplane software. There is a feature missing. The ALTIMETER needs to be "SET" using a rotary encoder to adjust the sub scale setting this is not working for some reason.

The software was written using something "processing" and resides on Rpizero. This in turn is connected to a "TEENSY" via a serial link to send and receive data from xplane

We want to fix the problem and then if possible look at further developments and perhaps come up with single board solution using microchip with built in graphics etc.

The example altimeter can be seen about 40 seconds into this video

https://youtu.be/VNdsDyhpuSI

I have set a budget but maybe we can cost this more accurately.

This project would suit somebody who has experience of graphics programming and aviation knowledge. Flight simulator experience would also be an advantage.