Thanks,
the user experience of installing and opening an external app is not perfect. I tested with the intent already, because this is often mentioned here.
Don´t get me wrong, I´m not looking for a "no code / one click" solution, I need a robust commercial solution that works on most Android Versions (17+) and devices.
Some of the free PDF Viewer here had performance issues and some rendering problems with transparency in PDFs. That´s why I asked.
I did some tests with radaeepdf this morning. That doesn't look too bad, and the 550€ sound ok as well.
anyway, thanks for your time.
Moosi