Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/stm32/stm32wl3/STM32WL33/MR_SUBG/AGC0_CTRL#0x0
AGC0_CTRL register
AGC hold time.
Start the AGC with a hold phase.
Enable the AGC
https://github.com/modm-io/cmsis-svd-stm32