The LB Bridge UDP and the LightBurn control UDP are two entirely different things. The UDP control is very limited in what it can do and it’s pretty much only to LightBurn, not LightBurn broadcasting out status. And the LB Bridge is currently very specific to Ruida controllers. It’s a simple passthrough - nothing more.
LightBurn does, however, already support air assist for Grbl. See more here:
It’s just the M8 command and the A3 pin (sometimes labeled coolant). You should be able to control air/ventilation with that and a simple relay no problem.