You say “no extra hardware” but you selected the hardware config that needs an external latch. I think if you change GPIOPINOUT back to ESP32_FORUM_PINOUT it should work
If the documentation wasn’t clear, please let me know where so I can update it. The Wiki is also editable if you want to add any clarifications that would have helped someone in your situation
Also, I’m sorry to say you’re one of the (hopefully few) users that upgraded to 4.0 in the last few days, before I changed the GFX layer API. Next time you update SmartMatrix Library, you’ll need to edit your sketch:
Just change #define SUPPORT_ADAFRUIT_GFX_LIBRARY to #define USE_ADAFRUIT_GFX_LAYERS, and SMARTMATRIX_ALLOCATE_BACKGROUND_GFX_LAYER to SMARTMATRIX_ALLOCATE_BACKGROUND_LAYER