Is it just me or does My Files app launch Google apps to view documents and photos?
I would expect that the Samsung app for that file type should open.
Aside from this, why this is frustrating at times is because once a document is opened, for example, there is no way to delete the file. You can only delete that type of file, like a PDF, from My Files directly. You may not delete the PDF from the Google PDF viewer, even after selecting the 3 dots in the corner of the screen.
