I have 4 different balls for the game. Starting with one ball visible and in use. When the total score gets to multiples of 5, I want to add a new ball into play.

So far I have:

      
import turtle

wn = turtle.Screen()
wn.title('pong by smelly bum')
wn.bgcolor('black')
wn.setup(width = 800, height = 600)
wn.tracer(0)  # stops window from updating so it needs to be done manually. this speeds up the game


# score
score_a = 0
score_b = 0
total_score = 0


"""
Ball
"""
ball1 = turtle.Turtle()
ball1.speed(0)
ball1.shape('square')
ball1.color('white')
ball1.penup()  # stops a line being drawn where the paddle has been
ball1.goto(0, 0)  # start psotion of the ball

ball1.dx = -0.1  # every time ball moves, it moves by this many pixels
ball1.dy = 0.1

"""
Ball 2
"""
ball2 = turtle.Turtle()
ball2.speed(0)
ball2.shape('square')
ball2.color('blue')
ball2.penup()  # stops a line being drawn where the paddle has been
ball2.goto(0, 0)  # start psotion of the ball

ball2.dx = 0  # every time ball moves, it moves by this many pixels
ball2.dy = 0.12
ball2.hideturtle()

"""
Ball 3
"""
ball3 = turtle.Turtle()
ball3.speed(0)
ball3.shape('square')
ball3.color('red')
ball3.penup()  # stops a line being drawn where the paddle has been
ball3.goto(0, 0)  # start psotion of the ball

ball3.dx = 0  # every time ball moves, it moves by this many pixels
ball3.dy = 0.1
ball3.hideturtle()

"""
Ball 4
"""
ball4 = turtle.Turtle()
ball4.speed(0)
ball4.shape('square')
ball4.color('grey')
ball4.penup()  # stops a line being drawn where the paddle has been
ball4.goto(0, 0)  # start psotion of the ball

ball4.dx = 0  # every time ball moves, it moves by this many pixels
ball4.dy = 0.09
ball4.hideturtle()

balls = [ball1, ball2, ball3, ball4]
ball_speed_x = [ball1.dx, ball2.dx, ball3.dx, ball4.dx]  # list of ball speeds that can be iterated through
ball_speed_y = [ball1.dy, ball2.dy, ball3.dy, ball4.dy]



while True:
    wn.update()

    for ball in balls:
        ball.setx(ball.xcor() + ball.dx)  # moves ball by dx
        ball.sety(ball.ycor() + ball.dy)  # moves ball by dy
        
        # border checking the ball
        if ball.xcor() < -390:
            ball.goto(0, 0)  # resets ball to centre
            ball.dx *= -1  # reverses direction of the ball
            ball.dy *= -1
            score_b += 1
            total_score += 1
            
        if ball.xcor() > 390:
            ball.goto(0, 0)
            ball.dx *= -1  # reverses direction of the ball
            ball.dy *= 1
            score_a += 1
            total_score += 1
           
        if ball.ycor() > 290:
            ball.sety(290)  # stops ball at border
            ball.dy *= -1 # reverses direction of the ball

        if ball.ycor() < -290:
            ball.sety(-290)
            ball.dy *= -1
        
    
        # make a list of balls and list of ball speeds so that i can index them in a loop to add balls during the game
        # make a variable that is true when total score is a desired value then false as soon as a ball is added.
             
        # want to find a way to put this in a more efficient way
        # maybe define a showturtle function and use a loop of ints
        if total_score == 5:
            ball2.showturtle()
            ball2.dx = 0.12
        
        if total_score == 10:
            ball3.showturtle()
            ball3.dx = 0.08
        
        if total_score == 15:
            ball4.showturtle()
            ball4.dx = 0.15

I want the addition of balls as the total score increases to be more automatic. so if i wanted to add ball5, I wouldnt have to add another if statement for total_score == 20, instead i could just define ball5 at the start of the code and it would work without additional code per new ball. I was thinking using a for loop, but dont know how i would implement properly.

furthermore is there a simple way to use loops for the creation of balls instead of repeating the same code to create them?

sorry if the code isnt quite minimal, ive left the paddle and the score display out.