Extract a part of a PDF page as a new PDF file
Allow an option to extract a part of a PDF page and save as a new file so it is a new file only showing what you want. This would be similar to cropping and then print to PDF the cropped page to eliminate the extra file size. The key is to keep the original file resolution / clarity.
You can extract complete page/pages using the pages app. Once extracted you can crop the new file as per your needs. This would maintain the original file resolution / clarity as required by you.
Please let me know if this works for you.