Depending on transition durations being used and the requirements of your design, you may be able to reduce file size by lowering the frames per second export setting without impacting the render.
When to reduce
In general, a slower transition duration means a lower FPS can be used. If exporting GIF/video fill, we recommend using an FPS of 30, which is the industry standard. Feel free to experiment to see what works for your situation.
How to reduce
You can choose from following FPS settings before starting the export process.
GIF: 10, 20, 25, and 60fps
MP4, WebM & Frames: 12, 24, 30, 48, and 60fps