Is it impossible to save "StringValue" through DataStore?

I won't my datastore to save "StringValue" is it unsupported or it is a script error it just changes it to a number?

Server Script:

--DataStores
local DataStore = game:GetService("DataStoreService")
local DataStore_oofs = DataStore:GetDataStore("SaveSystem_oofs")
local DataStore_rank = DataStore:GetDataStore("SaveSystem_rank")

--Create leaderboard
game.Players.PlayerAdded:Connect(function(player)
	--Create Leaderboard
	local LeaderBoard = Instance.new("Folder",player)
	LeaderBoard.Name = "leaderstats"
	--Create Values
	local Oofs = Instance.new("NumberValue",LeaderBoard)
	Oofs.Name = "Oofs"
	Oofs.Value = 0
	local Rank = Instance.new("StringValue",LeaderBoard)
	Rank.Name = "Rank"
	Rank.Value = "New Oofer"
	wait(1)
	--Load
	Oofs.Value = DataStore_oofs:GetAsync(player.UserId, Oofs.Value)
	Rank.Value = DataStore_rank:GetAsync(player.UserId, Rank.Value)
end)

--Save Data
game.Players.PlayerRemoving:Connect(function(player)
	--Varibles
	local Oofs = player.leaderstats.Oofs
	local Rank = player.leaderstats.Rank
	--Save
	DataStore_oofs:SetAsync(player.UserId, Oofs.Value)
	DataStore_rank:SetAsync(player.UserId, Rank.Value)
end)

If there is a way to save string values, please explain?

This is probably the solution.

--DataStores
local DataStore = game:GetService("DataStoreService")
local DataStore_oofs = DataStore:GetDataStore("SaveSystem_oofs")
local DataStore_rank = DataStore:GetDataStore("SaveSystem_rank")

--Create leaderboard
game.Players.PlayerAdded:Connect(function(player)
    local key = "id_" .. player.UserId
    --Create Leaderboard
    local LeaderBoard = Instance.new("Folder",player)
    LeaderBoard.Name = "leaderstats"
    --Create Values
    local Oofs = Instance.new("NumberValue",LeaderBoard)
    Oofs.Name = "Oofs"
    Oofs.Value = 0
    local Rank = Instance.new("StringValue",LeaderBoard)
    Rank.Name = "Rank"
    Rank.Value = "New Oofer"
    wait(1)
    --Load
    if DataStore_oofs:GetAsync(player.UserId) and DataStore_rank:GetAsync(player.UserId) then
    	Oofs.Value = DataStore_oofs:GetAsync(key)
    	Rank.Value = DataStore_rank:GetAsync(key)
    else
	return
    end
end)

--Save Data
game.Players.PlayerRemoving:Connect(function(player)
    local key = "id_" .. player.UserId
    --Varibles
    local Oofs = player.leaderstats.Oofs
    local Rank = player.leaderstats.Rank
    --Save
    DataStore_oofs:SetAsync(key, Oofs.Value)
    DataStore_rank:SetAsync(key, Rank.Value)
end)