Navigating Katee Robert's sprawling series can be a bit of a choose-your-own-adventure, which is part of the fun but also where it gets tricky. Her interconnected worlds—primarily 'Dark Olympus' and the 'Wicked Villains' series—aren't locked into a single, rigid order. If you're coming in fresh, I'd actually suggest starting with 'Neon Gods', the first Dark Olympus book. It's a fantastic gateway that introduces her signature blend of modern myth, high heat, and intricate politics in a setting that feels both fresh and familiar.
From there, you can stick with Dark Olympus chronologically ('Electric Idol', 'Wicked Beauty', etc.) for a consistent experience. The Wicked Villains books exist in their own pocket universe, retelling Disney villains with a dark, erotic twist, and they can be read independently anytime. However, reading 'Desperate Measures', the first Wicked Villains book, before 'Electric Idol' adds a delicious layer of context because a major character crosses over. That crossover is a neat 'aha!' moment that rewards the curious reader, but skipping it won't ruin either series. Personally, I read 'Electric Idol' first and then went back, and the reveal still worked in reverse, making me eager to dive into the other series to learn his backstory.