Question about upscaling video size

by jjj

Does anyone know why when I upscale videos to like 1920x1080 for even a small 10mb size, it turns into like 500mb-1gb for like a short 1-2min clip. But when I see others post upscaled videos that are like 30min long, they are the same size and resolution, am I doing something wrong or missing? Please help thank you