When I run the APK with Package Installer. After it runs I get the option of DONE or RUN It makes no difference which you choose nothing happens. If I go to the All Apps Page and tap the icon it disappears.
If I go to Settings>Apps NoteCase shows up but, the meaningful change I can make is to uninstall it.
I have tried downloading and installing directly using Firefox (download then open) on my device, and by downloading to my main system then transferring to my device (using both wired and WiFi) and installing it.
I've used both:
Samsung Galaxy Tab S6 (SM-T860) Android version 12
Samsung Galaxy A71 (SM-A716U1) Android Version 13
Robin