I see you seem fascinated by NPUs, here is probably one of the most recent publications that discuss performance comparison between NPU, GPU, and CPU for Edge computing case using YoloV5 model. And here's another benchmark provided by Google for its TPU product (Google Coral).
Given the circumstances, it's unlikely for current generation NPU to fulfill those heavy data tasks like upscaling video or generating video but for something like Edge computing they provide fairly performant solutions at affordable prices (in the case of NPU you can get them on Single Board Computer using Rockchip SoC especially RK3588 one). If you're using Raspberry Pi 5 or other SBC, you can get Google Coral (M.2 or USB version).
Maybe this resources can help your local LLM project.