See my Sept. 24 post above.
@tomw 's drivers work as intended. The problem is Switchbot's API hasn't been updated to support Curtain 3 (yet). It's anyone's guess when they'll add that device to their API.
In the meantime, the only way to make Curtain 3 work is by employing @fredpd 's workaround whereby you setup a basic scene in the Switchbot app that includes the Curtain 3, then call that scene in Hubitat using @tomw 's driver.
