I think jump power should be a thing that is added to zones and possibly scripts with a command.
Before you go off saying "But Dryym, We have a gravity setting in zones", That is not the same thing. The gravity setting changes the gravitational acceleration of the player in the zone. Jump power would change the upwards velocity given to the player when they press the jump key.
Currently, The gravitational acceleration in TM is around 36m/s², With the jump power being around 9m/s.
If I change the gravity to be that of earth, My character will jump really high because the jump power is really high, But they will fall down at the same rate as a human on earth would.
Conversely, If I increase the gravity, I will fall faster and jump lower due to the jump power being lower relative to the acceleration.
With a jump power option, You can change how high the player jumps independently of how much they accelerate downwards.
Perhaps this could even be set to allow the double jump to have a different power setting than the initial jump.