Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/stm32/stm32g0/STM32G0C1/FDCAN1/FDCAN_ENDN#0x0
FDCAN endian register
Endianness test value The endianness test value is 0x8765 4321.
https://github.com/modm-io/cmsis-svd-stm32