Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/stm32/stm32h5/STM32H523/RTC/RTC_SR#0x0
RTC status register
Alarm A flag
Alarm B flag
Wake-up timer flag
Timestamp flag
Timestamp overflow flag
Internal timestamp flag
SSR underflow flag
https://github.com/modm-io/cmsis-svd-stm32