converting data persistence to Data stores?

question says it all, i have a big game with many players that dont want to lose their data persistence, and for them to lose it would mean losing the players, and losing front page. Ive only found out recently i need data stores to transfer data across multiple places in a universe (i think). so i was wondering if maybe there was a way for when the player enters, load their data persistance, and then save it to data store (without loading it up first)

Data store code i have is here:

function onPlayerEntered(newPlayer)
		--Clone Data--
		local vs = script:WaitForChild("leaderstats"):clone()
		vs.Parent = newPlayer
		--Setup Intial Data--
		local Stats = vs:GetChildren()
		local S1 = {}
		for i=1,#Stats do
			local n = Stats[i].Name
			S1[n] = Stats[i].Value
		end
		--Get Data--
		if newPlayer.Name ~= "Player" then
			
			newPlayer:WaitForDataReady() -- This is the data persistence here;
			local score1 = newPlayer:LoadNumber("Lvl")
			
			if score1.Value <= 1 then -- maybe if the level value <=  1 then make data store?
				
			end  -- else, load data persistence, then delete it? (so it doesnt have to load it again?)
			
			local DataStore = game:GetService("DataStoreService"):GetDataStore(newPlayer.userId)
			
			if DataStore:GetAsync("Stats") == nil then
				DataStore:SetAsync("Stats", S1)
			end
			S1 = DataStore:GetAsync("Stats")
			
		end
		--Safely Load Data--
		local vv = vs:GetChildren()
		for i=1,#vv do
			local n = vv[i].Name
			--print(S1[n])
			if S1[n] ~= nil then
				vv[i].Value = S1[n]
			end
		end
end

game.Players.PlayerAdded:connect(onPlayerEntered)

for _,player in pairs(game.Players:GetChildren()) do
	onPlayerEntered(player)
end

game.Players.PlayerRemoving:connect(function(p)
	--Save Data--
	local DataStore = game:GetService("DataStoreService"):GetDataStore(p.userId)
	local stats = p.Data:GetChildren()
	local s1 = {}
	for i=1,#stats do
		local n = stats[i].Name
		s1[n] = stats[i].Value
	end
	DataStore:SetAsync("Stats",s1)
	--print("Saved "..p.Name)
end)

thanks for any help ~ Bubs

Thats actually what I was thinking. First, check if they have any Data Store saves, if there is nothing there, load up the Data Persistance, and transfer it to a Data Store. Then save that. From that point on, they are seen as having that data and it will no longer search for the old data (Which you don't need to call on.)

Because you may have players return to your game in a few months, it'd be useful to keep this as legacy.

Try it out in a seperate place before you go live though.