Some questions regarding the SPI configurations to interface with nrf24l01 radio transceiver
The radio module SPI bus can only communicate at up to 10 MHz, so you anyway have to configure the STM32 SPI peripherals to 10MHz or below.

So which peripheral on STM32 you choose is irrelevant, as they all can be used at max speed.

Unfortunately, with your choice of 42 MHz system clock, and the SPI clock divisors that are available, the divisor of 4 exceeds 10 MHz, so you must select at least divisor of 8, which provides you with 5.25 MHz SPI clock.

PCB and wiring may also limit how fast you can communicate.

The max SPI frequency of the STM32 is FCLK/2 because how it is designed. Since it operates the state machine at FCLK, it can toggle the SPI clock at every FCLK, which gives max clock of FCLK/2.