Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/stm32/stm32l5/STM32L552/FLASH/SECWM2R1#0x0
Flash secure watermak2 register
SECWM2_PSTRT
SECWM2_PEND
https://github.com/modm-io/cmsis-svd-stm32