Delay on is-visible state

[Denneee]

Hello,
I want to add a simple opacity animation on the slides that are visible. Sadly Splide is updating the is-visible classes a little late and the transition ist looking odd. See here https://codepen.io/dennee_/pen/MYeeerq.

For the active state there is a updateOnMove option. But he gives only one slide the active state and not all on the same page.
Anyone have an idea?
I could rely on the active state and make the animation individually for each slide with css, but i want a more global version that is working for all slides on my page with different amount of visible slides.

Im thankfull for any ideas!