Q. What countries observe July 4th?
A. All of them. The US celebrates Independence Day.
Do you have WAV Export copies of your raw, unprocessed readings? You need to do that. File > Export WAV (Microsoft) 16-bit (stereo or mono). We can’t take processing out of a reading and Audacity Projects do not save UNDO. Any mistake anywhere in the process and you get to read the whole work again.
Unless you have your WAV backup.
We published a new audiobook mastering technique greatly simplified that can get you to pass ACX in relatively few steps—assuming your reading works OK.
https://forum.audacityteam.org/t/audiobook-mastering-version-4/45908/1
Try that with a raw reading chapter and publish the ACX Check panel. If you have no raw readings, you can create a short forum test clip and see how the new mastering technique works for you.
http://www.kozco.com/tech/audacity/TestClip/Record_A_Clip.html
The new technique sets RMS (loudness) first and then cleans up the blue wave peaks in a second pass. If you read in a quiet environment, you could be out the door finished, or at worst need a little gentle noise reduction.
Koz