Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/Silicon Labs/EFR32BG22C224F512GM32/GPIO_S/USART0_CTSROUTE#0x0
CTS port/pin select
CTS port select register
CTS pin select register
https://github.com/cmsis-svd/cmsis-svd-data