Here's how to transfer your MS Store game account to the Unreal Engine 5 version of the game:

Step 1: Install the new UE5 version of the game from the MS Store

Step 2: Open the "old" version of the game to generate and copy the account transfer code

Step 3: Open the "new" UE5 version of the game. When asked "Do you already have an account?" select YES and paste your account transfer code.