Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/STMicroelectronics/STM32U599/SDMMC1/SDMMC_IDMACTRLR#0x0
DMA control register
IDMA enable This bit can only be written by firmware when DPSM is inactive (DPSMACT = 0).
Buffer mode selection. This bit can only be written by firmware when DPSM is inactive (DPSMACT = 0).
https://github.com/cmsis-svd/cmsis-svd-data