The pilot should get an indication that the prop is stalled once the dotted line (projected course) is below the artificial horizon
Aircraft is in a climb.
Aircraft is in a descent
The aircraft does have a require nose down attitude when at airspeed and trying to decent. The cause of its shape it does not rapid descent at speeds exceeding 80kts. You need to slow the aircraft down to rapid descent, I recommend "Arti-Stabli" ON and "Hover" ON then drop throttle for rapid descent. Give that a shot, also try to adjust throttle setting and make sure rear rotor indicator s are below 30 percent. This is due to a safety plugin that takes over throttle at low altitude.