SPI not working with MBED (was: Performance of XIAO with Sharp Memory Display)

No, I use D10 for MOSI and D8 for SCK as per https://how2electronics.com/wp-content/uploads/2022/05/Pinout.jpg

I used D4 for SS since I don’t think it makes a difference which one I use?

I had the oled and already tested it in real life. The project depends on being sunlight readable and fast update (so no eink) and the OLED was literally invisible.