NOSTR relays aren't truly relays when they start hosting notes and serving them to clients upon request.
That is the definition of "server", not relay.
Paradoxically geogram is delivering relays closer to the philosophy of NOSTR.
A relay in geogram only serves to connect two devices when they are behind firewalls and connect each other directly.
The devices themselves hold the data and pass it to other devices upon request. This is how true data sovereignty looks like. You carry it in your pocket, it is yours.
What another device to be your backup and host your data? Please do, just don't call it a relay. That would be a server. On geogram, each user with his own phone is a server for their own data.