Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/STMicroelectronics/STM32U031/LPUART1/LPUART_BRR#0x0
LPUART baud rate register
LPUART baud rate division (LPUARTDIV)
https://github.com/cmsis-svd/cmsis-svd-data