Why is my datastore script not working, even with print statements working?

--Datasave 

local players = game:GetService('Players')
local DSS = game:GetService('DataStoreService')
local runService = game:GetService('RunService')
local RS = game:GetService('ReplicatedStorage')

local dataStore = DSS:GetDataStore('MyDataStore')

local startingData = {
	Wins = {'IntValue', 0, 'leaderstats'};
	CraftingTables = {'IntValue', 0, 'stats'};
	DamageDealt = {'NumberValue', 0, 'stats'};
	TrailItems = {'StringValue', '', 'stats'};
	NoseTypes = {'StringValue', '', 'stats'};
}

local playersavedata = {}
local autoSaveInterval = 180


local function loadStarterData(plr)
	local STATS = Instance.new('Folder', plr)
	STATS.Name = 'stats'
	local leaderstats = Instance.new('Folder', plr)
	leaderstats.Name = 'leaderstats'

	for name, value in pairs(startingData) do
		local TABLE = value
		local typeValue = TABLE[1]
		local startingValue = TABLE[2]
		local folder = TABLE[3]

		local newValue = Instance.new(typeValue, plr:FindFirstChild(folder))
		newValue.Name = name
		newValue.Value = startingValue

	end
end

local function loadData(plr)
	local data

	local succ, err = pcall(function()
		data = dataStore:GetAsync(plr.UserId)
	end)

	if succ then
		print('Getting ' .. plr.Name.. "'s data was successful!")
	else
		warn('Something went wrong when loading ' .. plr.Name .. " 's data." )
	end

	if data then
		for name, value in pairs(data) do
			plr:FindFirstChild(value[3]):FindFirstChild(name).Value = value
		end
		print(plr.Name .. "'s data has been loaded!")
	else
		print(plr.Name .. ' has no data, generating new data.')
	end
end

local function saveData(plr)
	
	local data = {}
	
	for _, stat in pairs(plr.stats:GetChildren()) do
		data[stat.Name] = stat.Value
	end
	
	for _, stat in pairs(plr.leaderstats:GetChildren()) do
		data[stat.Name] = stat.Value
	end
	
	local succ, err = pcall(function()
		if data then
			dataStore:UpdateAsync(plr.UserId, function(oldValue)
				local previousData = oldValue or {DataId = 0}
				if data.DataId == previousData.DataId then
					data.DataId = data.DataId + 1
					return data
				else
					return nil
				end
			end)
		end
	end)
	
	if succ then
		print(plr.Name.."'s data has been successfully saved!")
	else
		warn('Something went wrong when saving ' .. plr.Name.. "'s data.")
	end
end

players.PlayerAdded:Connect(function(plr)
	playersavedata[plr] = tick()
	loadStarterData(plr)
	loadData(plr)
end)

players.PlayerRemoving:Connect(function(plr)
	saveData(plr)
end)

while true do
	wait(1)
	for _, plr in pairs(players:GetPlayers()) do
		if tick() - playersavedata[plr] >= autoSaveInterval	then
			saveData(plr)
			playersavedata[plr] = tick()
		end
	end
end

All the print statements are passing, but the data isn't saving. Thank you!