Welcome to Cadtutor. What you are offering is not a new solutions this have been around for me say 17 years, for where I worked.
But I have something extra for you, once you make the PDF's as single pdf's you can join them back into one, done this for 88 layouts but code looks for PDF's. It uses Ghostscript to rejoin the pdf's. Ghostscript is a free product and has lots of features. The code is ran via lisp.
The code attached also allows for a selection of layouts it has the Ghostscript code in it. You will need to edit the version of Ghostscript and its location.
A more advanced version checks for different company title blocks, eg landscape V's portrait.
Like others I would push for using layouts a much better way as you can take advantage of the viewport scale, I have multi code for making multiple layouts at scale matching your model space.
Multi GETVALS.lsp plotA3Pdfrange2.lsp