This is a Booster to fly like a Doubblejump in a lobby or other minnigames

You only need to put it in your worlds data pack folder and then type /function boost:setup

This booster has a Capacity of 3 Boosts with cooldown!
(Item for the boost is a Carrot on a Stick)

You could even fly if you set yourself the boost to a giant number like 9999999
(/scoreboard players set @s jboostcount 999999) and then spam the jump boost you will fly :)