Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/stm32/stm32wb0/STM32WB05/RADIO_REG_REG/ANTSW2_DIG_USR#0x0
ANTSW2_DIG_USR register
specifies the exact timing of the antenna switching during transmission at LE_1M baud rate (in AoD).
https://github.com/modm-io/cmsis-svd-stm32