Hello Camileck,
I would not know a plane that has all categories best. So i suppose you should prioritize some of them more and others less. My personal priorities are fdm and a functional cockpit.
If you want the most realistic fdm i have found in flightgear, then take this 737. The cockpit is good too, but on systems and model it is not the greatest.
https://github.com/soitanen/737-800There is also another development of the 737. You will have to compromise just slightly on the fdm. It is almost as good. But you win on the systems and model.
https://github.com/YV3399/737-800YVMaybe there are also aircraft that have extreme good systems and model. But i do not use them because i prioritize fdm. Others can better advertise these planes than me.
Ow, and i see you registered recently. Welcome on board.
Kind regards, Vincent