Print duplicate pages sequentially within a large file

I am trying to create duplicate invoices sequentially numbered.  I have created my file in InDesign with a single copy of each numbered page and now want to print with two copies of each page one after the other to form the duplicate.  I thought it would be a simple matter of switching off the "collate" button on the print dialogue, but that doesn't work - I still get two separate files.   I tried creating a pdf and copying the pages, but there are 2000 and I can't work out how to do this as a bulk action to keep the pages paired.   Please could I have a steer on how best to do this?

I'm working in Windows on the lastest versions of Adobe and InDesign (Sept 2023) 

Thanks