Gutenberg has some downloadable master indexes that relate filenames to titles and authors. You can find them on this page:
https://www.gutenberg.org/wiki/Guten...ings_of_EBooks
You probably want to download the latest one at the top of the list.
Then you can put it in a text editor and create a batch file to do the renaming for you using any fairly sophisticated text editor such as Notepad++.
You can extract the files by doing a search on *.epub or *.txt or whichever you're interested in. If you want more than one file type I suggest renaming a single file type at a time. It'll be easier. But that's not really required.
This is going to require a bit of skill at creating batch files but it's the sort of thing anyone comfortable with MS-Dos has probably done many times. It requires a little skill, not a great deal.
Another, probably easier way to do this if you have some computer programming skill is to write a small program to read a carefully parsed version of the index and rename files based on it. This would only require minor programming skills but it would require some.
I haven't seen the ISO but based on what you've said my guess is that it's very doable and not really that complicated, depending on your skills.
Barry