According to this post by an acclaimed hero, at least the WH51 should be supported by the FSK build, as far as I can understand:
https://community.openmqttgateway.com/t/lilygo-ttgo-lora32-v2-1-1-6-915-mhz/2492/15?u=hifij
Though there a 915MHz variant is used, while I am trying to catch it on 868MHz.