Y'know, if we apply their own logoc to it, Julie isnt the world's first lead trans VA. See, the reason they're so adamant that Maddie Blastein doesn't hold that honor is that even though Meowth was in every episode and his actions usually affected the plot in a very major way, he wasn't the absolute sole main focus of the plot. Well let's take a look at Gen Zed. While Shona is indeed a main character, she shares the spotlight of the show with three other characters, meaning that she isn't the only one the plot focuses on, ergo she doesn't fit their criteria for a lead character.
That really sucks too, it sure wouldn've done wonders for the industry if they were to introduce the first lead trans character, but sadly they come just a smidge short of reaching that goal

. But just to show that there's no hard feelings, here's a cute little picture to show you have my sympathy Julie: