To be fair, we're deluding ourselves if we think that a handful of hobbyist aircraft developers can even come close to doing a "study level" simulation of aircraft systems on any "modern" airliner
Admittedly I don't really know what a "study level" simulation is supposed to be. I googled the term, and while there didn't seem to be any official definition, closest I found was
here:
"I feel an SLS should be something that pilots can get hold of, use real world manuals to fly the addon and the addon will respond exactly as a real world aircraft/FFS would."
Let's first note that there is no simulation that will 'respond exactly as a real world aircraft' would. A real world flies in exact physics, a simulation flies in coefficient schemes to make the computation feasible. Most of the time the differences are small, but I have no trouble coming up with a situation in which they grow large (my favourite example is passing through an externally generated shockwave).
Second, the real experiences always provides all sorts of cues which the simulation can not provide (easily) - that starts with exact force feedback and ends with zero gravity - in the real Shuttle it is eminently easy to deduce you've just had a three engine failure because you are weightless - in the simulation you don't have this most important and obvious cue.
Third, to the degree that you can patch software of devices in reality, the simulation would have to run an emulator for the real software (which usually happens to be proprietary) - but then it would also have to provide simulated sensor info for the real software.
So even the goal that 'you can always do what the manual says' simply can't be realized in principle.
What definition is meant then?
Something where the simulation prepares you well for the real thing in terms of control experience and procedures?
We seem to have quite some aircraft like this (maybe not airliners though).
Something that doesn't break when you start poking at it or intentionally create an off-nominal situation?
To give an example for poking - say I have a device in the cockpit which I can switch on or off - perhaps a screen, or a gyro. That device has a power consumption. If I switch it on and off while looking at the bus voltage very closely, will I see that the voltage changes - and will I be able to deduce the rough power consumption from the voltage loss?
Obviously, there has to be plenty of stuff 'underneath' what you usually see in the surface to make a simulation even moderately poke-proof.
So maybe before discussing whether any particular aircraft is 'study level' we should define what is meant by these words?