The problem can be reproduced using the qt provided hangman demo project.
[built on macOS Bug Sur (11.6.7)]
The following lines:
CONFIG += qmltypes
QML_IMPORT_PATH = $$PWD/hangmangame.h
QML_IMPORT_NAME = Hangman
QML_IMPORT_MAJOR_VERSION = 1
Fails to register the Hangman qml import and you get the following error on Android:
W libhangman_arm64-v8a.so: qrc:/qml/MainView.qml:53:1: module "Hangman" is not installed
NB: This may be an intermittent bug as opening the CMakeList.txt project and running that worked and then when going back to the .pro project this then worked ok.