What is the program flow to get multiple SPI ports to run at the same time?
I did something like this before (around 2006), I need to speed up the programming of SPI flash devices in our production and we want to do parallel SPI operation for all the 8 flash device. So thinking out of the box, what I did is:


create a fixture which can slot in 8 devices
the CS pin, CLK, MOSI are all connected in common to all device. So all flash devices, receive the commands from these pins at the same time.
For reading, I used a full port (PORTB0 to PORTB7) to connect to the individual MISO of the flash devices.


This was a success. It used SPI bitbanging and involves bit-shifting to form the data read from the port. But still very fast than accessing or reading an SPI device one at a time.

But I see that you are using PIC32MZ2048 and only 2 SPI device, maybe you can try exploring the QSI (Quad Serial Interface) if it can achieve your needs without resorting to bitbanging.