i have been coding by myself for a year and i wanted to make a similar game but it doesn't work with me either. My code is close to identical to yours,

import turtle

# create Screen
wn = turtle.Screen()
wn.bgcolor("light green")

# Create player
player = turtle.Turtle()
player.color("blue")
player.shape("triangle")
player.penup()
speed = 1

#create the inputs
def left():
    player.left(30)

def right():
    player.right(30)

#Key input actions
turtle.listen()
turtle.onkeypress(left, "Right")
turtle.onkeypress(right, "Left")

while True:
    player.forward(speed)

i've tried everything and it just doesn't work. I think that it does not work because the program is not listening (although i fired the function listen()) because i have put this line in my program:

def print_test():
    print("works")

with this in the keyinputactions

turtle.onkeypress(print_test, "Space")

and it gave me nothing as an output. I think you might have the same problem. I however do not know how to fix this because of my lack in expertise.

I hope this helped, although i do not think that you are still working on this problem after 2 years.