Hola Csaba -
xxx
When I started flying with airlines, my first position was flight engineer on 727.
Then I became flight engineer 707, then first officer 727, then first officer 707...
Back then, it was the normal career path.
Flight engineer, then first officer, then captain...
And you get 2 licences. One is Flight Engineer, the other one is Commercial Pilot.
xxx
Happy contrails