You just need to make sure the video sections are stored in a concatenatable format (like mpeg or m4s), and then you can literally use cat.

if anyone has the resources to figure out this magic incantation, it would be Google.

It’s not that difficult a command compared to what is possible with ffmpeg. But it’s also a pretty common enough task that literally the first result for using DDG with “ffmpeg concatenate without reencoding” gave: https://stackoverflow.com/questions/49371422/how-to-merge-tw...