Because, as the feedback at the beginning of the topic, DT4 has increased the size (may increase by 10 times) after commenting on these (the situation I have encountered at present, it only refers to the OCR pdf file downloaded from the Internet Archive), and I used PDFPen to remove OCR layer, used PDFPen for OCR, and the processed files can be annotated normally when imported into DT4 and DTTG4.
But the PDFPen I bought many years ago is version 12, which will not be updated. It will not support the new macOS system in the future (it can no longer be installed on new computers above M4/macOS 15). The price of the new Nitro PDF is too high, so I have changed ForceEditablePDFs to TURE, and I don’t want to buy any other products (although some have been purchased, their upgraded version OCR files can’t be annotated by DT either.)
Thank you for your suggestion to PDF Resolution. In the past, I have tested more than a dozen documents, 200dpi and As Source, and the latter can maintain a smaller file size more often. Maybe the file I got is more suitable for this setting. Thank you.