Possibility to embed/attach a PDF-file which opens at specific page number

Yeah, this can be done by uploading the pdf as a file attachment, then add #page=4 etc at the end of the URL, as below.

https://articulateusercontent.com/rise/courses/KOVEN0k6kNKDP-cS8coP4AIX-6k8TBbK/N0c0HyQ-kRgy26fp-Skills%2520Signposting%2520Guide.pdf#page=4 

Then I use iframe generator to create the embed code and use the embed block. eg

<iframe src="https://articulateusercontent.com/rise/courses/KOVEN0k6kNKDP-cS8coP4AIX-6k8TBbK/N0c0HyQ-kRgy26fp-Skills%2520Signposting%2520Guide.pdf#page=4" name="page 4" scrolling="no" frameborder="1" marginheight="0px" marginwidth="0px" height="400px" width="600px" allowfullscreen></iframe>

This works for me on Chrome, Firefox, and Edge, but not on my Phone browsers.