standard nostr relays don't relay events to other relays, even know the name would suggest that. it's a bit confusing. to run a high quality relay, you would just have a large server with high system resources and storage.
Discussion
So there are two different types of relays?
there's custom relays now that do relay your events to other relays such via a custom implementation or some are using blastr. https://github.com/MutinyWallet/blastr