adding PDF pages/ replace by a new PDF

I would like to request a feature that allows users to upload a new version of a PDF to replace the current PDF in an existing deck, while keeping all the flashcards and notes associated with that deck, as I make some annotations on the PDF using my iPad while studying with the flash cards using my laptop. Additionally, it would be very helpful to have the ability to add extra pages to an existing PDF deck, so I can update or expand my study materials without having to create a new deck and manually transfer my flashcards. Thirdly, I would like to request the order of flashcards is according to the pages of the pdf, so I can edit the flash cards more conveniently. Thankyou!