NumberValue doesn't change. How to make it work?

this is my stamina script. it does somehow work but numbervalue doesnt change so i had to script whole thing in one script (i want to make a dash part a separate script and make stamina gui based on numbervalue). "stamina" variable is a numbervalue. also its localscript if that matters.

local player = game.Players.LocalPlayer
local character = player.Character
local humanoid = player.Character:WaitForChild("Humanoid")

repeat wait() until player.Character

local UIS = game:GetService("UserInputService")

WalkingSpeed = 16
RunningSpeed = 32
JumpingPower = 50
stamina = script.Parent.Stamina.Value
local isRunning = false
local isJumping = false
local canRun = true
local canDash = true
local gui = game.StarterGui.Movement
local text = gui.InfoGui.StaminaText

staminaDrain = 0.05
staminaRegeneration = 0.1

local tapped = false
local dashCooldown = false

humanoid.WalkSpeed = WalkingSpeed
humanoid.JumpPower = JumpingPower

UIS.InputBegan:connect(function(key)
    if key.KeyCode == Enum.KeyCode.LeftShift and humanoid and not isRunning and canRun then
        isRunning = true
        humanoid.WalkSpeed = RunningSpeed
        while isRunning and stamina > 0 do
            text.Text = stamina
            stamina = stamina - 1
            wait(staminaDrain)
        end
        if humanoid then
            humanoid.WalkSpeed = 16
        end
        isRunning = false
    end
end)

UIS.InputEnded:connect(function(key)
    if key.KeyCode == Enum.KeyCode.LeftShift and humanoid then
        isRunning = false       
    end
end)

UIS.InputBegan:Connect(function(key)
    if key.KeyCode == Enum.KeyCode.LeftShift and humanoid and canDash and not dashCooldown then
        if tapped == false then
            tapped = true
            wait (0.25)
            tapped = false
        else
            dashCooldown = true
            character.HumanoidRootPart.Velocity = character.HumanoidRootPart.CFrame.lookVector * (stamina + 100)
            stamina = stamina - 25
            wait(3)
            dashCooldown = false
        end
    end
end)

humanoid.StateChanged:Connect(function(oldState, newState)
    if newState == Enum.HumanoidStateType.Jumping then
        stamina = stamina - 10
    end
end)


while true do
    if not isRunning and stamina < 100 then
        stamina = stamina + 1
        text.Text = stamina
    end
    if stamina >= 25 then
        canRun = true
        canDash = true
        humanoid.JumpPower = JumpingPower
    elseif stamina <= 10 then
        canRun = false
        canDash = false
        isRunning = false
        humanoid.JumpPower = 0
    end
    if stamina >= 10 then

    end
    wait(staminaRegeneration)
end

thanks in advance