Acrobat 2020 editing the Header or Footer in a PDF Document

Question

I use Acrobat 2020 (pro) to edit a large document. When I insert a "Header" I can use the tool to edit "headers and footers" like in a Word Document. https://www.adobe.com/au/acrobat/hub/how-to/how-to-use-headers-footers-in-pdfs.html I have to do this because the document is puzzled of 100 different documents and is printed at the end. The header contains a Page-Number and when I update the header, Acrobat will find the pagenumbers in all this textboxes and update the numbers (or text). I made a sample of a random document. The pagenumbers I look for are the one of the top. (there is not on every page a number) sample_Doc The pagenumbers are made by Acrobat and if I add a page, Acrobat will count the pages new when I make an update. Now, I will find this pagenumbers in the document and a textbox nearby. Is there anybody who knows how to do this? Acrobat will find it, then eg VBA or Java Script will find it too. But how?