Where do you have connected the GPS? In the BetaFPV manual i found the following info:

"Please ensure UART1 is disabled when using SPI Receiver: if vou need to use the external receiver, please configure UART1 to be set as Serial RX"

When Walksnail is UART2 and you need the ELRS SPI Receiver, so there is no UART left? i was going to use the same FC for a similar project, but i discarded it because of this info.

I think that the betafpv doco is poorly worded / lost in translation. If you have an spi receiver then it doesn't conflict with any uarts as they (spi and uart) are different communication buses.

I have gps on uart2 and the ws 1s vtx on uart 1 with msp turned on. Works just fine!

SWEET