How to vary the initial velocity of a jump based on hold time?

Question

What I want to do is, the longer player holds the screen, the longer distance the object will jump when they release the hold.

Here is my code:

private float timeBeginTap; 
switch (touch.phase)
{
    // Finger start touching the screen
    case TouchPhase.Began:
        print("Start tapping");
        timeBeginTap = Time.time;
        break;

    // Finger leaving the screen
    case TouchPhase.Ended:
        //when finger release,the object jump
        float timeHolding = Time.time - timeBeginTap;
        Debug.Log($"The player1 touched the screen for {timeHolding} seconds.");

        Vector2 jumpVelocity = new Vector2(timeHolding, timeHolding);
        rb.velocity = rb.velocity + jumpVelocity;

        break;
}

So with the code above I can get the value like 0.6324167, or 0.423567 for timeHolding, which is the amount of time that user hold the finger on screen.

And I able to make the object jump by using this code below:

Vector2 jumpVelocity = new Vector2(timeHolding,timeHolding);
rb.velocity = rb.velocity + jumpVelocity;

But the distance traveled or "force" with which the object jumps is very small and it doesn't make sense. Therefore I make an attempt with the code below:

float right = 5;
float up = 10;
Vector2 jumpVelocity = new Vector2(right*timeHolding,up*timeHolding);
rb.velocity = rb.velocity + jumpVelocity;

With the code above, the distance is of course longer. But it feels constant and not dynamic, because the relationship between the Vector2's X and Y value is always constant.

Therefore my question is,

What is the correct way to define the values of X and Y for a Vector2 object based on the value of Time?

If I missed anything, please guide me in the right direction.

Desired Outcome:

For example,the velocity added to the box is to let the box jump from pole to another pole and stand on it.

The velocity is define by using the time user hold on the screen,the longer the user hold on screen,the greater the velocity,means the x,y value of Vector2 is define by the timeHolding.

Now when I hold the screen for the long time,the box will jump to the 3rd or 4th pole,and it not guarantee will reach the pole.Like everything is by chance.

What I want is,the box will jump from 1st pole to 2nd pole,from 2nd to the 3rd and continuously.At the same time,the velocity to go higher or lower and the distance is depends on the time user hold the screen.

This is what I want and my limited understanding of the problem.