True airspeed vs Indicated Airspeed vs Mach Number. You’re seeing Indicated Airspeed (IAS) which is the speed tape. Check the lower left corner of the PFD for your True Airspeed (TAS). IAS is always lower than TAS the higher you go.
The 301 knots top end speed specification is in TAS, not IAS.
And yes, “The Barberpole is a Destination, Not a Limitation,” but I wouldn’t make any sudden attitude changes at that speed, you’ll overstress the jet and end the game.