Cannot store Instance in data store. Data stores can only accept valid UTF-8 characters.?

Cannot store Instance in data store. Data stores can only accept valid UTF-8 characters. second script:

local ds = game:GetService("DataStoreService"):GetDataStore("Data")

game.Players.PlayerAdded:Connect(function(plr)
	local key = plr.UserId.."_id"
	local save = plr.stats.ins
	
	local savel = ds:GetAsync(key)
	if savel then
		save.Value = savel[1]
	else
		local nfs = {save}
		ds:GetAsync(key, nfs)
	end
end)

game.Players.PlayerRemoving:Connect(function(plr)
	local key = plr.UserId.."_id"
	local save = plr.stats.ins
	ds:SetAsync(key, save)
end)

first script:

game.Players.PlayerAdded:Connect(function(plr)
	local folder = Instance.new("Folder", plr)
	folder.Name = "stats"
	
	local ins = Instance.new("NumberValue", folder)
	ins.Name = "ins"
	ins.Value = 1
end)

script not save oh i was wrong but thank you