@bryn is the screen one of those with the red PCB? The ili9341? If so your in luck. If you read through my guide in my signature, I have a post in there about speed boosts. The initial setup is slow, but the screen can cope with higher speeds
@rich1812 when I Google rs6-21 I find Audi alloy wheels

my guide may help you too, we would just need to translate those pins. I think you will only need the first group