The template is very easy to edit in the free 3D program Blender, even if you've never worked with graphics programs.
You can add ANY flag to your animation very quickly.You can save the finished image in absolutely any size in pixels.
Video example - https://youtu.be/M9iVY7qRF-I
Watch quick Blender tutorials and tutorials on editing:
Other templates: https://www.cgtrader.com/priymak