Software developer here. MSFS and X-Plane have very similar flight model. XP calls it "Blade Element Theory. MSFS calls it “Surface Element Model”. But the underlying principles are essentially the same. Their implementations are somewhat different (MSFS needs to accommodate certain legacy aircraft parameters from FSX). But both have the potential to be very accurate for desktop usage. Just needs a lot of tuning to get the behavior you want out of it. And the more data you could get on the real life aircraft the more accurate final results would be.