I just tested this myself in the G1000 Cessna 172 using the live build (1.32.27.0). On the ground with the parking brake on, applying full throttle would max out the engine at approximately 2300 rpm. However, I was able to taxi to the runway and take off normally. Once airborne, the engine would rev higher to about 2500 during the climb and departure. In my experience, the Cessna 172 is working fine.
Thanks,
MSFS Team