Why can't the images be compressed more? They make up the bulk of the file size. That it is running on unity as to why images cannot be further compressed makes no sense to me. Thank you for the reply BTW
This has been answered, but in case you want a more technical answer...
The images can be compressed more, but they're already webp (and the videos webm), so compressing them more would require sacrificing quality.
Someone could do this, but that person would run into the problem of getting the images back into the game. With Ren'Py, when you crack open an rpa archive it (rpatool) puts the files in the same directory as the rpa archive. Ren'Py will see these and use them instead of the copies in the archive. So you can compress the images and delete the rpa. Unity doesn't work like that. You need to have the assets in the same place they came from, which is way harder than just leaving the new files lying around.