SimRacing is a hobby in which you Race/Drive etc Racing/Driving Simulators.(iracing, assetto Corsa, rfactor, liveforspeed etc etc)
Never heard SimTruck we generally use Truck Simming and we use Truck Simulator software/game.
Again, for flight i use Flight Simming. On the other hand we can discuss if MSFS is a Flight Simulator or not. SimFlight sounds like more “something trying to simulate flight”