AudioBookConverter VS mp4v2

https://github.com/yermak/AudioBookConverter Apparantly this is a good program to use. You should be able to convert them to a single m4b file and it should keep all the chapters intact.

Source: https://github.com/yermak/AudioBookConverter

Audiobookconverter can combine multiple mp3s into a single mp4

Audiobook Converter - Takes anything not an M4B and makes it an M4B (and can add some basic metadata to an M4B). For Plex, I've found it useful to have one file for playback vs. all the mp3 files (plus it's a lot cleaner)

I also had this issue with Audiobookbinder and switched to AudiobookConverter for longer book bindings

However, I only went through the trouble because I didn't want audio quality to be affected at all (nothing to be encoded again, only removed). If you are not too concerned about audio quality, there is definitely programs out there on Mac that can chapterize files. M4btool is pretty powerful and there is Audiobook converter. I've heard AudioBookBinder might work as well, though I think it is older at this point.

some audiobooks come in multiple mp3 so i merge a books tracks all into one file to save the headache of adding meta data to sometimes 100s of files for one book. I use https://github.com/yermak/AudioBookConverter to merge mp3s into m4b which I've seen being a standard for audiobook file format but mp3 will also work if you like that extension.

Yermak's AudioBookConverter is phenomenal. Development is on hiatus due to the war in Ukraine, but the most recent version is still available on Github.