Her zoning has many layers to it while not being as technical as Skarlets timing on different projectiles. You eat a lot of chip on the way in, and when you're close she has soooo many things to trick you with.
First off, she has arguably the best AA game of the roster, you cant jump at her. She has crazy good buttons to stuff your approach. Her standing normals have a good hitbox while not exposing her hurtbox. Once you respect that she has a throw that sends you fullscreen, and then she has really good pokes, she has wall which is as tricky to punish as Scorpions teleport. If you wait for the amplify to FB you might miss the regular punish, and the d1 into wall that also sends you fullscreen. And even block her shit has so much pushback. It just feels like it's never your turn against a decent Cetrion