Unity's addressable system lets you load and unload assets as you need it. But you need your own server, Unity's cloud server or similar to accomplish that.
You should also consider the size and resolution of the images you're putting in. If your monster is larger than is needed to display on a 10" tablet - reduce its size and reimport it into Unity.
You could also consider importing the monsters in components and putting them together in Unity - see sprite sheets.
Thank you for your reply and links :)
I saw this: https://support.google.com/googleplay/android-developer/answer/9859372?hl=en&utm...
It says Play Store hosts 1.5 Gb of resources? Or am I understanding it wrong?
Yes, you can use that https://android-developers.googleblog.com/2020/06/introducing-google-play-asset-... They have a Unity plugin. I don't know if it still works (Amazon's plugin for Unity doesn't work).
But then you're limited to Google Play and wouldn't be able to publish your game anywhere else. With addressables, you can publish your game anywhere.
