Nice work—the overlay effect with the original shot definitely helps tie together the narrative. I've used this technique before myself on some of my music videos, but the hardest part for me is finding shots that feel like they're part of a continuous story and/or visual language. One place that has longer videos to choose from (if you can stand the lower resolutions and older formats) is the
Internet Archive. Though I wonder if with some of the new upscaling, stabilizing and reconstructing AI techniques that can be used to enhance footage if this won't be a trove very soon.