How to Create an Animated OBS Overlay

Create image sequence

Use photoshop to create video timeline and animation the opacity

Export the file - Render to video and select image sequence.

Set alpha channel strate unmatt options.

Use FFMpeg to convert image sequence to .mov

ffmpeg -i img%04d.png -vcodec png

Note: use .mov for transparency

Add media source to OBS

Import the .mov file.