I have never thought of flying as "fun" although I am passionate about flying and have derived huge satisfaction from being a professional pilot.
My advice is if you are passionate about flying (yes even with the autopilot engaged) then go for it but don't be under any illusions about the airline industry which is now mainly in a race to the bottom with terms and conditions for pilots in a spiral dive.
In my opinion the flight deck of an airliner is not a place to have "fun" as the task is deadly serious. That doesn't mean you have to be poker faced and not have a bit of banter from time to time though.