I recommend starting with SG-1 though. It’s the original series, with Atlantis it goes a bit off the rails in my opinion. Still decently enjoyable to watch, but it feels like an attempt at rebooting the successful formula of sg-1, except without the relatability. Also SG-1 is more tongue-in-cheek, there are several episodes where they poke fun at themselves, and RDA is just being RDA anyway.