It is reasonably easy to determine your controller identity.
Common interfaces are 8080-8, 8080-16, 4-wire SPI.
Common ribbon pinouts are 37-way.
Your ribbon is 18-way withone dummy.
I would put money on 4-wire SPI
So you have to do some detective work for the interface.
Then keep your fingers crossed that a parallel 8080-x connects to contiguous Port pins.
An SPI interface is tied to hardware SPI pins.
I am not familiar with GD32. I would be much happier with regular STM32.
I would just hope you have SPI ILI9341.
Yes, if you can determine the schematic, it looks a pretty good deal. You get a smart enclosure with electronics to match automobile wiring.
On the other hand, you could add a ILI9341 display to a STM32 Nucleo board. Develop in comfort.
But spend serious money on electronics and enclosures.
David.