It can be incredibly difficult to interpret a HUD in a rapidly changing unusual attitude
(I don't know about 'incredibly' but certainly dynamic).....
Since FZ evidently utilize HGS at times I'll add another comment about about HGS use here in TOGA that fits with the pitch attitude 'call' discussion.
For both takeoff and go-around the HUD displays a dashed line that represents target pitch attitude for the maneuver so the raw information is already there.....however command steering (flight director 'ball') is for the FPV not the 'attitude symbol', i.e. 'boreline'), both 'ball in the FPV' and 'boreline on the dashed line' theoretically resulting in the same flight profile.
Normal phases of flight the FPV sits about 2-6 degrees below the pitch symbol. At 0.0-0.2g the FPV might end up slightly above or nearly aligned with the pitch attitude symbol. I've observed various responses to this.....