UpdateAsync Broke After Changing Something? [SOLVED]

So, I've been looking for answers all over for days on end. I haven't been able to find anything new for a while now, so I think asking a question here is my last option.

I've changed values around, I've changed the structure of the code, I've changed how the script accesses the values. But with no success. It did work at one point, but I needed to change it and now I can't remember for the life of me what I did.

If anyone can help, it would be greatly appreciated, here is the code:

local dataStoreService = game:GetService("DataStoreService")
local StatStore = dataStoreService:GetDataStore("StatStore")

game.Players.PlayerAdded:Connect(function(player)
    game.Workspace:WaitForChild(player.Name)
    player:WaitForChild("leaderstats")

    local Key = player.UserId

    local Leaderstats = player.leaderstats
    local Steps = Leaderstats.Steps
    local SpeedBoost = player.PlayerGui.Codes.SpeedBoost

    local DefaultData = {
        ["Steps"] = 0,
        ["SpeedBoost"] = false
    }

    local Stats
    local recieved, notRecieved = pcall(function()
        Stats = StatStore:GetAsync(Key) or DefaultData
    end)

    if recieved then
        Steps.Value = Stats
        SpeedBoost.Value = Stats
        print("Stats were recieved")
    else
        StatStore:SetAsync(Key, DefaultData)
        print("Stats were not recieved")
        warn(notRecieved)
    end

    wait(0.1)

    local Stats = {
        ["Steps"] = Leaderstats.Steps.Value,
        ["SpeedBoost"] = player.PlayerGui.Codes.SpeedBoost.Value
    }

    while wait(300) do
        local saved, notSaved = pcall(function()
            StatStore:UpdateAsync(player.UserId, function(oldValue)             
                print("Stats were auto saved!")

                return Stats
            end)
        end)
    end
end)


game.Players.PlayerRemoving:Connect(function(player)
    local User = game.Players:FindFirstChild(player.Name)

    local Leaderstats = User.leaderstats
    local NewSteps = script.Parent.StepLoop.Steps
    local Steps = Leaderstats.Steps
    local SpeedBoost = User.PlayerGui.Codes.SpeedBoost

    local DefaultData = {
        ["Steps"] = 0,
        ["SpeedBoost"] = false
    }

    local Key = User.UserId

    local Stats = {
        ["Steps"] = Leaderstats.Steps.Value,
        ["SpeedBoost"] = User.PlayerGui.Codes.SpeedBoost.Value
    }

    local success, result = pcall(function()
        StatStore:UpdateAsync(Key, function(oldValue)
            return Stats
        end)
    end)

    if success then
        print("Stats were saved")
    else
        print("Stats were not saved")
        warn(result)
    end
end)

(SpeedBoost is a Bool value and Steps is an Int value)