I have small frequently modified *.pri source-libraries, purpose of those pri's is to add headers and sources, do aux tasks like copy file. Those libraries are at same or higher directory level than the project that will use them and must have access to parent project variables (e.g ANDROID_PACKAGE_SOURCE_DIR)
example of *.pri:
#AnFeature/AnFeature.pri
HEADERS += $$PWD/anfeature.h
SOURCES += $$PWD/anfeature.cpp
INCLUDEPATH += $$PWD
OTHER_FILES += $$PWD/android/src/example/anfeature/anfeature.java
QMAKE_POST_LINK += $$QMAKE_COPY_DIR $$shell_path($$PWD/android/src/example/anfeature) $$shell_path($$ANDROID_PACKAGE_SOURCE_DIR/src/example/anfeature)
Looking how to implement that kind of stuff via CMake 3.19 or newer