Hey dude! I am here with you. I am struggling with IPA size as well, except my game is pushing the 2gig limit and fails to package when it reaches that.
If you were to package out a blank 3rd person project, the size is a couple hundred MB’s of just engine dependencies as what not. You can’t really get around that with UE4 right now. I am assuming the additional MB’s in your case is your map, and the assets on your map/ in your content folder.
You could try following the official doc page on reducing IPA size but you probably have already tried that?