The following warning message appears when trying to install on Windows 11

Windows protected your PC
Microsoft Defender SmartScreen prevented an unrecognised app from starting. Running this app might put your PC at risk.

Application:
telstory-converter
Publisher:  
Unknown publisher

It works! Just to make that clear from the get-go. Relatively easy to set up and the conversions are done very quickly, so if you're not familiar with these guys, don't worry that they might be scamming you. They're legit.

The only reason I'm taking a star off, at least for now, is that the program's advertised ability to split by chapter is one of the things that sold me on it, and based on my limited experience so far, it does a very bad job of it. It seems to split books based on a very brief and nonvarying period of silence, which does not at all correspond to actual chapters. In fact, it's so bad that sometimes even the narrator's chapter announcements are split in two. Fortunately, the program also gives you a single file to work with, and I was able to quickly do a much better job chaptering the three books I used for testing by simply setting a separate splitter software to split on 3250 ms of silence. This kind of manual splitting is not always so easy, though, especially with some older recordings, so hopefully the Epubor guys will come up with a much more intelligent way of having their own software do this automatically. I use another free software for chaptering Audible downloads and 9 out of 10 times it does an excellent job of splitting by actual chapters, so it seems that this should be possible.

If the chapter stuff is not important to you, though, or not as important as just being able to have your own copy of a book that you can listen to at your leisure, without having to maintain a subscription, this is an easy recommendation. Another reviewer mentioned the lack of proper tags, and the automatic file naming could also use some work, but those things can quickly be done in a software like MP3Tag, so not as a big a deal to me personally as the chaptering feature.