Hi raffiniert,
1.What happens if use hardware spi instead of soft spi mode?
//Adafruit_SharpMem display(SHARP_SCK, SHARP_MOSI, SHARP_SS, 144, 168, 2000000);
Adafruit_SharpMem display(&SPI, D4, 144, 168, 2000000);
2.Can you increase the clock frequency which is 2MHz by default? XIAO nRF54820 can be increased up to 8MHz, but I don’t know if a Sharp allows up to what MHz.
I do not have a Sharp, so I can only check up to the compilation.