My datastore isn't loading properly, what's going wrong?

I have a datastore for Diamonds, Levels, and Exp. Diamonds load just fine, the issue is with Levels and Exp. For some reason, they 'save' (as in it prints in output that they saved just fine) but they don't load as the new values. I've already posted this question, but I've changed a few things based on suggestions. So, I was told to replace part of my code and to put them all on one script for efficiency. Sadly, this didn't fix my issue so I figured I would reword it. I'm going to give all of the 200+ lines of code to see what's going wrong as a whole.

To be extra clear, the issue is either that it's not actually saving, or something is making it impossible to load. Something to keep in mind, I have another script that may be causing issues. It adds value to Exp until it reaches a certain number, then resets Exp to 0 and adds a Level. I'm not sure if I need to use a different method for that though, and if that's the issue.

Datastore Script:

-- Datastores
local DataStoreService = game:GetService("DataStoreService")

local dsDiamonds = DataStoreService:GetDataStore("ds_Diamonds")
local dsLevels = DataStoreService:GetDataStore("ds_Levels")
local dsExp = DataStoreService:GetDataStore("ds_Exp")

-- Adding stats and checking for data
game.Players.PlayerAdded:Connect(function(player)

    -- Folders
    local leaderstats = Instance.new("Folder")
    leaderstats.Name = "leaderstats"
    leaderstats.Parent = player

    -- Making Storage
    local Diamonds = Instance.new("IntValue")
    Diamonds.Name = "Diamonds"
    Diamonds.Value = 1000
    Diamonds.Parent = leaderstats

    local Levels = Instance.new("IntValue")
    Levels.Name = "Levels"
    Levels.Value = 1
    Levels.Parent = leaderstats

    local Exp = Instance.new("IntValue")
    Exp.Name = "Exp"
    Exp.Parent = leaderstats

    -- Create Data Vars
    local datadiamonds
    local datalevels
    local dataexp

    -- Check for Data
    local success, errormessage = pcall(function()
        datadiamonds = dsDiamonds:GetAsync(player.UserId.."-diamonds")
        datalevels = dsLevels:GetAsync(player.UserId.."-levels")
        dataexp = dsExp:GetAsync(player.UserId.."-exp")
    end)
    if success then
        Diamonds.Value = datadiamonds
        Levels.Value = datalevels
        Exp.Value = dataexp
    else
        print("There was an error getting data")
        warn(errormessage)
    end

end)

-- Saving when player leaves
game.Players.PlayerRemoving:Connect(function(player)

    local success, errormessage = pcall(function()
        dsDiamonds:SetAsync(player.UserId.."-diamonds", player.leaderstats.Diamonds.Value)
        dsLevels:SetAsync(player.UserId.."-levels", player.leaderstats.Levels.Value)
        dsExp:SetAsync(player.UserId.."-exp", player.leaderstats.Exp.Value)
    end)
    if success then
        print("Data Saved Successfully")
    else
        print("Data could not be saved")
        warn(errormessage)
    end

end)

game:BindToClose(function()
    -- When ready to shutdown
    for i, player in pairs(game.Players:GetPlayers()) do
        if player then
            player:Kick("Server shutdown, join back in a moment!")
        end
    end
    wait(5)
end)

Exp->Level Script:

local t = 0
local timeneeded = 1
local player = game.Players.LocalPlayer

while true do
    t = t + 1
    wait(1)

    if t == timeneeded then
        --experience + 10
        player.leaderstats.Exp.Value = player.leaderstats.Exp.Value + 1
        t = 0
    end

    if player.leaderstats.Exp.Value >= 20 then
        player.leaderstats.Exp.Value = 0
        player.leaderstats.Levels.Value = player.leaderstats.Levels.Value + 1
    end

end