Making flags for AOE2DE

Hi there, are there any people with expertise in Blender? I have made a flag and would like to introduce them as modded flags to the AOE2DE game. Could someone assist me to make them work with appropriate rendering and brightness suitable for the game?

The blender file is below. It’s a flag of the republic of Pisa. And I would like to make more.
https://drive.google.com/drive/folders/1m8mwf-TPidW7N7zR4dwROUBxvUzeBrMf?usp=sharing