are you using Mbed for the software? With Mbed, there is a SPI class that can be used for the communication. The linked repo uses bit banging for SPI in softare, which is much slower compared to the hardware SPI units.
This is a lib for Mbed:
using
unfortunately, 16 bit SPI transfers with STM32 in mbed-os-6.15.0 are broken and a previous or newer, fixed version must be used.