No plane in turbo can stay at full manifold pressure all the way to their cruise altitude (as required by most turbo-pistons) in MSFS.
I disagree with this statement. I’ve taken the Seneca V to 20,000 ft (the rated critical altitude for the Seneca’s turbochargers), and it holds manifold pressure as expected all the way through the climb. There are a few problems with turbocharger logic in MSFS, but holding manifold pressure is not one of them. One of the biggest problems is fuel/air mixture. The sim calculates fuel/air mixture for a turbo engine the exact same way it does for a naturally aspirated engine – based on the ambient air density at altitude rather than the density in the engine’s intake manifold. This results in excessively rich fuel mixtures and loss of power as the airplane climbs.