StepUp - a mod that will allow you to climb to the height of one block without jumping, if you quickly run and approach the block, then the player will very quickly and simply climb it, but if there is another block behind this block, the player will make a full jump, which slow it down a lot.

Thanks to this mod, the player will instantly climb the ladder of blocks without slowing down. The mod has a key to turn this mode on and off, see the control settings.