How do you split all pages to same size?

Hello, I found a way to do this automaticly by playing with some print settings in acrobat (I am using the latest version as of 11/30/23. First open your file with double pages and click the button to print. First make sure you are printing to a Acrobat Pdf (found by clicking the box at the top left of the print screen labled "Printer:"). Then select the "Properties" button just to the right of that box. Midway down that box you should see a box labled "Adobe PDF Page size" click the "Add..." button on the right of the window. Here you can type in a new title for this Paper name and adjust the size of the paper. In my case I was splitting a photo copied book that had two book pages per pdf page, so I set the width to 8.5in (standard page size) and set height to 5.5in (half of the standard page size). Then click "add/ modify" and select your newly made page name as your page size. Next, select the "layout" page and click on the "advanced" button near the bottom right of the window. In this window near the top right under the "paper/ output" line select your newly made paper name as the "Paper Size:" click okay on all windows until you get back to the original print window. You should now see a dotted line in the print prewiew, indicating that it work. Finally, click print and select the desired location of your now split document. 

Are comfortable with InDesign? One option is to use the place multipage pdf script to place all pdf pages into a single page InDesign file, where you can clearly see the spread pages in the pages panel and add a facing page, which will split the spread pages into single pages upon export to a new pdf. The advantage is you can confirm all pages are positioned correctly to the spine and cross-over spread pages (a map for example) will remain as spread pages*. You can add blank pages if needed to move pages to the correct side of the book and insure the total page count is divisible by 2 or 4 (depending on binding).

*change the InDesign document setup to facing pages, after placing the pdf

Read this:

https://community.adobe.com/t5/acrobat-discussions/how-to-split-a-pdf-with-spread-pages-to-single-pages/td-p/3142122