Unity in app purchasing build size

Hi, I’m making a game for Android and I’m using Unity 2021.3.25f1.
I want my game to be playable on Google Play Instant. But for that to be possible my app/game needs to be under 15MB. My game has been around 12MB until I added IAP. I did some testing and without IAP my .apk size is 12.6 MB. With the IAP package, my .apk size gets to 17.1MB. This means the IAP package is 4.5MB (33% the size of my original game)

Is there a way to reduce the IAP package size or strip certain parts I don’t need?

Thanks!