Just an update, I was able to re-map the MISO pin from GPIO19 to GPIO12. This was done by simply passing the new pin into the slave driver function. I'm guessing the reason the other pins didnt work is due to the "disadvantage: talked about in this thread. So using the technical reference manual 4.1...

Hello, I was able to use the SPI Slave API using the original pins and communicate with the master. I am now trying to switch the pins to the other side of the ESP32, however I'm not sure how to do so. If anyone could point me in the right direction or any links to an example of IO Muxing the ESP32 ...