This burning issue has NOTHING to do with any of the troubleshooting tips that you outline!! It is a "BUG" that was introduced in iTunes 184.108.40.206 and continues in iTunes 220.127.116.11. If you follow threads that myself and other commenters have opened you will find that dozens of users are experiencing this issue.
In my case I can say without any question that this is a software bug. Why? I have the advantage of multiple computers and have iTunes installed on 4 of 5 of them (though one of them is the "host" system for my music collection which tops 75,000 songs). When I first encountered the issue on my primary system (after using Apple Software Update to upgrade from iTunes 18.104.22.168 to iTunes 22.214.171.124) I attempted to replicate the problem on one of my other systems that was still running iTunes 126.96.36.199. The same content (formed into a playlist to match up to the contents of a set of classical MP3's) that produced a burn error under iTunes 188.8.131.52 burned an audio CD WITHOUT any problems when iTunes 184.108.40.206 was the host software.
To further validate that the issue involved a "bug" with iTunes 220.127.116.11 I then used Apple Software Update to upgrade the iTunes version on the computer that had just been used to successfully burn an audio CD (while running iTunes 18.104.22.168) to iTunes 22.214.171.124. After the upgrade (and of course with the requisite restart of the computer) I attempted to burn the same playlist to an audio CD. What was the result? FAILURE!! So with the only variable being the version of iTunes software (126.96.36.199 vs. 188.8.131.52) used I got a successful CD burn with 184.108.40.206 and a failed CD burn with 220.127.116.11. I spent 6+ years as a server administrator for a very large governmental unit (yes that means Windows) and spent a lot of time troubleshooting issues. Trust me when you have a "single" variable in what does or does not produce the desired result you have found the problem about 99.99% of the time.
When Apple quietly released iTunes 18.104.22.168 I upgraded my primary system to the latest version (again using Apple Software Update) and found that the issue persists.
So it is time that Apple addresses this issue (I know from community postings that they have gotten multiple phone calls with several support staff promising that the issue is being escalated to the engineering team).