A scroll-driven, media-heavy site and a fast one are not opposites — they fail together when performance is treated as a QA pass instead of a design input.
We set a performance budget before any hero video is scoped: how many megabytes of media per screen, how many concurrently playing videos, how much JavaScript runs on first paint.
Pausing offscreen video, lazy-loading everything below the fold and shipping WebM-first with MP4 fallback are not optimizations we do later — they are the default we design inside of.