Pay in freight is generally less than passenger (although there are a couple exceptions like Fed-Ex...but they prefer high-time military US citizens).
You are right, there are indeed a couple of exceptions
In my company most of the crews come from many PAX companies. The salary in (GOOD) freight companies can at least be twice more than in passenger companies, on the same type of aircraft.
But yes, if you are a wannabe, it might be hard to get a job. Try Ryanair
