TouchScreenButton joystick freze into main scene - v4.4.1.stable.official

I use v4.4.1.stable.official godot version.
I tried to use a TouchScreenButton node to create a joystick , two image : circle and a knob with this script into joystick2d_v001.tscn scene

@onready var knob: Sprite2D = $knob  # Reference to the knob node
@onready var max_distance = shape.radius  # Maximum distance the knob can move
@onready var knob_center: Vector2 = Vector2.ZERO  # Dynamically calculated knob center
var touched: bool = false

func _ready() -> void:
	# Calculate knob_center based on texture size and initialize the knob's position
	knob_center = texture_normal.get_size() / 2
	knob.position = knob_center  # Ensure the knob starts at the center
	set_process_input(true)  # Enable input processing

func _process(_delta: float) -> void:
	if touched:
		# Restrict knob movement within the max_distance
		knob.position = (knob.position - knob_center).limit_length(max_distance) + knob_center
	else:
		# Reset the knob to the center when touch ends
		knob.position = knob_center

func _input(event: InputEvent) -> void:
	if event is InputEventScreenTouch:
		if event.pressed:
			# Convert the input position from global to local coordinates
			var local_touch_position = to_local(event.position)
			if local_touch_position.distance_to(knob_center) <= max_distance:
				touched = true
				knob.position = local_touch_position
		else:
			touched = false  # End touch
	elif event is InputEventScreenDrag:
		if touched:
			# Convert drag position to local coordinates and restrict movement
			var local_drag_position = to_local(event.position)
			knob.position = (local_drag_position - knob_center).limit_length(max_distance) + knob_center

This is main scene script I used this script for the joystick scene but is freeze and not change position of knob , why ?

@onready var sprite_2d: Sprite2D = $Sprite2D  # Reference to the sprite that moves
var joystick_scene: PackedScene = load("res://joystick2d_v001.tscn")  # Path to joystick scene
var joystick_instance: TouchScreenButton

func _ready() -> void:
    # Load and instantiate the joystick scene
    if joystick_scene and joystick_scene is PackedScene:
        joystick_instance = joystick_scene.instantiate() as TouchScreenButton
        add_child(joystick_instance)

        # Set joystick position relative to its parent node
        joystick_instance.position = Vector2(200, 200)  # Adjust position in the scene
        print("Joystick successfully added.")
    else:
        print("Failed to load joystick scene!")

func _input(event: InputEvent) -> void:
    if joystick_instance:
        # Forward input events to the joystick
        joystick_instance._input(event)

func _process(delta: float) -> void:
    if joystick_instance:
        # Calculate the joystick's directional input based on knob position
        var joystick_position = joystick_instance.knob.position - joystick_instance.knob_center

        # Move the sprite based on joystick input
        if joystick_position.length() > 0:
            sprite_2d.position += joystick_position.normalized() * delta * 200  # Adjust speed
        print("Joystick Position: ", joystick_position)