English is not my mother language so I struggle with understading the word "creep" haha
https://printhouse.co.uk/2012/01/what-is-creep/
Assuming this will be professionally printed and bound, the printer's imposition software will compensate for the folded sheets pushing away from the binding. You should not attempt to make any adjustment—just set the document dimensions to the final trim size.
I don't think you want to help the printer in any way with the imposition. If you need to provide a separate document for the cover it can be setup as 4 facing pages with the cover on page 1 and the back cover on page 4. Let the printer impose it the way they want to on the press sheet:
