Content comes from ALL the relays. That's the point. It's just that some relays are faster than others, and also you have to consider that the relays and nostr are still being evolved in real time. What you need to do is find the relays that are FAST for you, and limit the amount of trash/universe data flooding your nostr. Like i said, get 4-6 paid relays, and add 2-3 non paid relays that are fast and reliable. Even then, you're still going to experience types of lag depending on your client, the relays, and other factors. As more support comes out, things will get faster.