How to render a smooth timelapse from 30FPS video?
I ain't sure if this will work but better than nothing!
Here two of my approaches to this problem:

Warp Stabilization
Software such as Mocha, AE and many others have Warp Stabilization. What is means is that it can automatically stabilize the clip based on the frames and it somewhat relates to Machine Learning approach to Big Data.

Converting to 24fps
You can open in in a video editor and manually delete clips based on your own human ability to judge by looking at the previous and next frame. As we know our eyes can think 24fps as a smooth video clip, you may try this manual fix technique by deleting at 3-5 frames per second of your video!


Giving an opinion based answer, I think warp stabilization would render quite great results.