Another topic discussed this recently, so that may be a good place to start:
@K6CCC gave an explanation in that topic similar to what @carverofchoice said, and I found that useful. I wasn’t able to concatenate the video files using VLC, but FFmpeg worked for me when I tried that. The community member who posted the topic eventually used Avidemux to accomplish the goal, and I can see that it’s available for macOS, but I have no personal experience with that software (and haven’t touched a Mac in years).