[Quoth]

I'd export/convert the epub to docx.
Then in LO Writer (or years ago MS Word) clean it up a bit and set what ever page size I want. Then export as PDF.

Codex means leaves, like book pages. I know webpages stupidly are still like scrolls, which are 2000+ years out of date. Really a 110″ page is a scroll. Amazingly there are still faxes that can take a roll and can work as printers. Also plotters now use an inkjet head instead of pens and the big ones are a carriage fed from a roll.
So you can still print scrolls! Just not on laser printers or regular sheet fed inkjets.

Only desktop systems will definitely scroll giant page PDFs on screen. Not sure what iOS and Android will do. Many ereader would run out of RAM. That's why ebooks are typically one file per chapter (or near invisible scene break) though it's hidden by the "envelope" which is essentially a zip file. With epub you can rename it to zip and see the files and extract them!