Kotlin How to create a template application
Solution 1:
I have in my projects two ways.
Library, as you mention. I use it when there are routines that are common to several projects. It is possible to change color patterns and some style details. But it is often plastered.
Flavors - Build Variants https://developer.android.com/studio/build/build-variants
With build variants you can create one project/app with two versions, chandind only wat you need. This option is very good when you want to change color, endpoint, style, show or hide some system functionality. I use it and it's very good.