There are free online pdf-to-epub converters, though of course anything you send to them could be read or distributed illicitly by them if they wanted. First one I Duck’ed was
I don’t use Pages for iOS but I know it can (1) import PDFs essentially as uneditable images, and (2) export files as ePub. If you don’t need to edit a pdf perhaps it can be used to creat an ePub, but I assume the file would be huge as it would consist of ‘images.’
There are options in the App Store, but the reviews tend to be all over the place. Here’s one free option with IAP:
Thanks! Currently I’m looking at this company: http://overnight-scanning.eu to send books to and then have them scanned and sent back for me to read in Apple Books or Kindle on the iPad. It will cost me a little money, but it will save a lot of time.