Compressing Epub File

Hey KDP experts!

I have successfully squashed my ebook from 33MB, down to 4.1MB using the tool at https://www.onlineconverter.com/compress-epub

But I was really hoping to promote it for 99 cents and I can't do that unless it falls under 3MB.

I've already manually resized and compressed all the images inside. If I re-run the compressed epub file through the compressor again, the pages/images get screwed up.

Any other magic someone can recommend?

Gratefully,

Matt Ramsey