Not physically ideal but good jump

GravityJump.cs

using UnityEngine;
using System.Collections;

public class GravityJump : MonoBehaviour {

    public float fallMultiplier = 2.5f;
    public float lowJumpMultiplier = 2f;
    
    Rigidbody2D rb;
    
    void Awake() {
        rb = GetComponent<Rigidbody2D>();
    }
    
    void Update() {
        if (rb.velocity.y < 0) {
            rb.velocity += Vector2.up * Physics2D.gravity.y * (fallMultiplier -1) * Time.deltaTime;
        } else if (rb.velocity.y > 0 && !Input.GetButton("Jump")) {
            rb.velocity += Vector2.up * Physics2D.gravity.y * (lowJumpMultiplier -1) * Time.deltaTime;
        }
    }
}