🚀 go-pugleaf

Fonts can reside in a number of other places. Further, if you have
your Preferences set to preserve fonts, then it will be quite
difficult  to get rid of them.

First change your Preferences to turn off "Remember Missing Font
Names" in the compatibility section.

Then open all files in your book (Shift + click on File > Open All
Files in Book) and accept the missing font warnings.

Next, save all files in the book (Shift + click on File > Save All
Files in Book).

You can reset your Preferences at this point if you wish.

Now you should be able to create a PDF of your book. Tip: it's usually
better to have all files in the book open before doing the SaveAs to
avoid the situation that you're running into.