If you did not watch it yet, my @ManjaroARM #PlasmaMobile
video about the @kde @PINE64 #PinePhone
has chapter markers now that may save you some time!
(Sorry for the glitches BTW. I used mencoder to concatinate the videos and that wasn't a good idea. Snap and deb install of kdenlive had both failed to deliver a working video editor, and I only tried the Flatpak later (which, of course, works brilliantly).)