@Mind-Brain You code will not actually increase the height during the jump (tested it out). The increase in z jump is already after the jump so it’s not actually doing anything but increasing a value that has already been triggered.
I believe this is the effect what the OP was looking for
The higher the value on the lerp the higher the jump extension. This actually makes the character travel higher during the jump
Normal press = normal jump
Hard press = high jump
I also added that once the character starts falling the offset is no longer added (falls normaly)