Yes, I'm just as curious as you on _why_ does a staging setup needs the same amount of resources as prod.
All of my staging setups are on a ~$15 Hetzner server, with a GitHub Action to `docker compose build && docker compose up -d` remotely, with an Apache service with a wildcard certificate and dynamic host names. We have 3..n staging setups, with each PR spinning up a new staging site just for that PR.
It's been working with us for years, for a team of 10 developers.
Genuine question.