More like a few dozen kilobytes to a handful of megabytes. If you look in F-Droid you can find some good old apps where graphics are either small or it uses the default styles for buttons and the like
Looking at a tiny utility app I made 6 years ago, it's 9KB, most of which will be the default things the compiler includes
According to my phone it's 25MB.
There's no assets, not even an app icon.
I have no idea what would be taking up more than a few hundred kb, let alone 25MB.
Tools can vary depending on what language you used. For example i wrote a small app using flutter and i used the flutter's app size tool.
But there are alternatives that reuse the OS's libraries nowadays.
A "hello world" Android starts at ~5MB.
It is possible to make it smaller if choosing some non-default different tools.
The “default” recommendation is clearly Android Studio plus Kotlin/Java.
Other tools are smaller.
Use plain Java, regular Android views, handle yourself the ifdefs for Android versions, and the 5 MB won't be there.