Changing entity Y motion doesn't work when falling

Hi, i'm very new to Forge, i'm trying to make the player bounce when he hits the ground with specific boots, similar to slime blocks. But I can't figure out what to do to make entity.setMotion work for Y motion, it works for X and Z axis but not Y.

The only condition where it can work is when I fall on a slime block, so I guess there's probably some methods to call to properly cancel the fall but I don't know these

Here's the code (i started from auto-generated code from a procedure and edited it after) :

package net.mcreator.ctfa.procedures;

import net.minecraftforge.registries.ForgeRegistries;
import net.minecraftforge.eventbus.api.SubscribeEvent;
import net.minecraftforge.event.entity.living.LivingFallEvent;
import net.minecraftforge.common.MinecraftForge;

import net.minecraft.world.World;
import net.minecraft.util.math.BlockPos;
import net.minecraft.util.SoundCategory;
import net.minecraft.util.ResourceLocation;
import net.minecraft.item.ItemStack;
import net.minecraft.item.Item;
import net.minecraft.entity.Entity;

import net.mcreator.ctfa.CtfaModElements;

import java.util.Random;
import java.util.Map;
import java.util.HashMap;

@CtfaModElements.ModElement.Tag
public class SlimeBounceProcedure extends CtfaModElements.ModElement {
	public SlimeBounceProcedure(CtfaModElements instance) {
		super(instance, 18080);
		MinecraftForge.EVENT_BUS.register(this);
	}

	@SubscribeEvent
	public void onEntityFall(LivingFallEvent event) {
		if (event != null && event.getEntity() != null) {
			Entity entity = event.getEntity();
			double i = entity.getPosX();
			double j = entity.getPosY();
			double k = entity.getPosZ();
			double damagemultiplier = event.getDamageMultiplier();
			double distance = event.getDistance();
			World world = entity.world;
			
			for (ItemStack itemStack : entity.getArmorInventoryList()) {
				
				Item item = itemStack.getItem();
				if (item.getRegistryName().toString().equals("ctfa:slime_block_armor_boots")) {
					
					if (itemStack.attemptDamageItem((int)(distance * 0.6), new Random(), null)) {
						itemStack.shrink(1);
						itemStack.setDamage(0);

						if (world instanceof World && !world.isRemote()) {
						((World) world).playSound(null, new BlockPos((int) i, (int) j, (int) k),
								(net.minecraft.util.SoundEvent) ForgeRegistries.SOUND_EVENTS.getValue(new ResourceLocation("block.slime_block.break")),
								SoundCategory.BLOCKS, 1.f, 1.f);
						}
						else {
							((World) world).playSound(i, j, k,
								(net.minecraft.util.SoundEvent) ForgeRegistries.SOUND_EVENTS.getValue(new ResourceLocation("block.slime_block.break")),
								SoundCategory.BLOCKS, 1.f, 1.f, false);
						}
					}

					entity.setMotion(entity.getMotion().x, (int)(distance * 0.75), entity.getMotion().z);
					entity.isAirBorne = true;
					event.setCanceled(true);
	
					if (world instanceof World && !world.isRemote()) {
						((World) world).playSound(null, new BlockPos((int) i, (int) j, (int) k),
								(net.minecraft.util.SoundEvent) ForgeRegistries.SOUND_EVENTS.getValue(new ResourceLocation("block.slime_block.fall")),
								SoundCategory.BLOCKS, 0.4f, 1.f);
					}
					else {
						((World) world).playSound(i, j, k,
								(net.minecraft.util.SoundEvent) ForgeRegistries.SOUND_EVENTS.getValue(new ResourceLocation("block.slime_block.fall")),
								SoundCategory.BLOCKS, 0.4f, 1.f, false);
					}
				}
			}
		}
	}
}