How to automatically reverse page order in a PDF file with Adobe Acrobat

Run this script from the JS Console

(How to use the Console: https://acrobatusers.com/tutorials/javascript_console )

	var t = app.thermometer;
	t.duration = this.numPages;
	t.begin();
	for (i = this.numPages - 1; i >= 0; i--)
	{
		t.value = (i-this.numPages)*-1;
		this.movePage(i);
		t.text = 'Moving page ' + (i + 1);
	}
	t.end();

Hi there 

Hope you are doing well and thanks for reaching out. 

You're right, manually reordering over 300 pages would be impractical. While Acrobat doesn't have a direct "Reverse Pages" button, you can achieve this using JavaScript within Acrobat or through an Action Wizard (available in Acrobat Pro DC).

To batch change page numbers in Adobe Acrobat, you can utilize the "Action Wizard" (also known as batch processing) feature. This allows you to apply a series of actions, including adding or updating page numbers, to multiple PDF files at once.
When you apply one or more routine commands to your files, you can save time and keystrokes by using an action—a defined series of commands with specific settings and in a specific order that you apply in a single step. You can apply an action to a single document, several documents, or a collection of documents.

For more information, please check the help page https://adobe.ly/3IbmnS5 and see if that helps.

Hope this information will help.