vidcutter ultimately didn't help in this process. I built it from source and then tried the flatpak, but for all of its beauty, it hung or crashed when importing common but dated formats and containers, handling more than a few clips, and didn't allow precise jogging for splitting (when it didn't hang or crash). It's good for trimming up a smartphone video, but it's not on par with an NLE.
I ended up giving up and scripting out most of the project in ffmpeg and dvdauthor. If you know how to use core utilities, it's such an exercise in tedium struggling against underdeveloped front ends.