You only talk about engine parameters. What about correct spin behavior, working seatbelts and correct icing visualization and effects? Tire pressure simulation?
Just wanting to point out, even if the engine simulation was perfect, there would be the next "issue".
You have to keep in mind MSFS, while it may be used as a serious Sim to some degree, remains a home-user software with relatively cheap addons.
For the fidelity you are looking for, only a professional sim dedicated to one aircraft could provide that, which would cost thousands.
Blacksquare and A2A provide the best piston and turboprop GA addons on the market, each with their own strengths and weaknesses. If both don't fulfill your needs, nothing on the MSFS platform will.