Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/stm32/stm32h7/STM32H723/OctoSPII_O_Manager/CR#0x0
OctoSPI IO Manager Control Register
Multiplexed mode Enable
REQ to ACK Time
https://github.com/modm-io/cmsis-svd-stm32