The isClimbing bool get initialized as false although the first frame in Update() should do the trick anyway since if the Player is not touching a ladder isClimbing is always set to false in the first if statement.
I just added 2 if statements so the middle one is setting the isClimbing as true as soon as the player has a “climbing” input and the actual climbing code only gets executed if the player isClimbing …hope that makes sens but works for me.
So the Player character only interacts with a Ladder if you press up or down.