In Premiere Pro, how do I set the fps of a video to publish?
You need to select minimum bitrate for video, especially if your video have only 1 image.
If you will look how h264 codec works, you will know that it creates one "basic frame" each 'n' frames and then it creates "intermediate frames" only with areas of pixels which were changed.

I have tried some variants and can show you how fps affect on file size. And how keyframe distance affect to file size.
https://drive.google.com/open?id=1ZobMxAzPQi2NaVfLDa5wYrHN87tIc11h

You can look at these 5 files.



Sample_minimum video BitRate_10 fps_keyframe distance = 300 - audio bitrate 320kbps.mp4 has size - 1 348 883

Sample_minimum video BitRate_10 fps_keyframedistance - standart - audio bitrate 320kbps.mp4 has size - 1 943 816

Sample_minimum video BitRate_30 fps - audio bitrate 320kbps.mp4 has size - 1 983 552

Sample_minimum video BitRate_30 fps_keyframe distance = 300 - audio bitrate 320kbps.mp4 has size - 1 544 303

Sample_without video - audio bitrate 320kbps.mp4 has size - 1 210 771 B

Minimum bitrate you can set here: