Data store save and load

hello dev forum,
i am making a tycoon where if u start the game you can load all of your previous tycoons.
i want to make a data store for each tycoon and show them to the player on entering the game.
this means i need to be able to search for all the keys who match the players id. but i have no clue how to do that. please help me.

When a player joins or leaves, you should save/retrieve their data with a key format like "Player_"..plr.UserId so you can consistently retrieve their data without discrepancies.

You should also have just a single data store and save dictionaries to it to reduce the amount of code clutter you’ll have.