Smalll size vs. Large size

Hi, I’m working on a project that has very small dimensions. When at 100% it’s a tiny box on my screen. Whenever I zoom up to work on it, it gets very pixelated. Nothing should be getting pixelated because all the assets are vectors but I’m wondering if it’s because anything at 200% zoomed up would be pixelated… When I render it as an mp4, it fills my whole screen instead of staying a tiny box and as when i previewed it, it’s very pixelated.
My question is; would it make sense in the future to work on larger dimensions and then when done precompose it and put it in a new comp and scale the whole comp down by like 80%. Would that help?