"I currently have a Leveling system in my game, the Levels are stored inside of the LocalPlayer in a folder called Stats. Script something that saves the players levels when they leave the game. No leaderstats. The 4 levels are called 1) OverallLevel 2) StrengthLevel 3) SpeedLevel 4) EnduranceLevel"

-- server script 
local DataStoreService = game:GetService("DataStoreService")
local LevelStore = DataStoreService:GetDataStore("LevelStore")

game.Players.PlayerRemoving:Connect(function(player)
    local stats = player.Stats
    if stats then
        local data = {
            OverallLevel = stats.OverallLevel.Value,
            StrengthLevel = stats.StrengthLevel.Value,
            SpeedLevel = stats.SpeedLevel.Value,
            EnduranceLevel = stats.EnduranceLevel.Value
        }
        local success, err = pcall(function()
            LevelStore:SetAsync(tostring(player.UserId), data)
        end)
        if success then
            print("Saved data for " .. player.Name)
        else
            warn("Failed to save data for " .. player.Name .. ": " .. err)
        end
    end
end)

game.Players.PlayerAdded:Connect(function(player)
    local success, data = pcall(function()
        return LevelStore:GetAsync(tostring(player.UserId))
    end)
    if success and data then
        local stats = Instance.new("Folder")
        stats.Name = "Stats"
        stats.Parent = player

for levelName, levelValue in pairs(data) do
            local valueInstance = Instance.new("IntValue")
            valueInstance.Name = levelName
            valueInstance.Value = levelValue
            valueInstance.Parent = stats
        end
    elseif not success then
        warn("Failed to load data for " .. player.Name .. ": " .. data)
    end
end)