Your choice, Some of the early 2000s cartoons had pilot episodes that started in the 90's, What A Cartoon Show. But Outside those examples, we had Samurai Jack, I have a bunch of DVD episodes of it sitting on my shelf in case I want to binge watch those. There is a 5th season of it which is also worth watching for adults who still watch the show today. I think it is a good example of quality animation, late 2000s TV shows like My Little Pony Friendship is Magic had a smoke dragon episode similar to what was in Samurai Jack, Dragonshy, which I thought was interesting.
Sorry I cannot discuss this further, I am about to watch a completely different TV show, but enjoy your early 2000s cartoon watching Woohoo, and remember, we are friends.