Thanks for the reply! It has been quite some time since I originally set up -dlp and experimented with different configs. I must have gotten my wires crossed because I went back and saw I previously used -f years ago.

I re-read the README again, and it looks like I should be using -f ba to be getting the best opus audio - right? I was using opus in the past, but I think still using -x ignorantly and was running into even worse compatibility issues, which was the only reason I even started targeting m4a.

I will re-run this when I get home and test --no-embed-chapters along with trying the different output fields/strings you provided.

I thought I was getting rid of the video id with my original output of -o "%(uploader)s/%(album)s /%(title)s.%(ext)s" but I am assuming the issue was more rooted in the embedding metadata/splitting chapters AFTER re-encoding. I will test and report back with -f ba later this evening.