Trouble pitching an ongoing ensemble drama with a whodunnit throughline

I'm preparing to go to networks (whenever they start buying again) with an ongoing ensemble drama with a whodunnit throughline running through the first season (the pilot is written), and I'm REALLY struggling with my pitch. Although the series arc works well, the problem is condensing it all into a twenty-minute pitch. For one thing, covering multiple character arcs in such a short space in a way that flows is tough. But then ALSO threading in a whodunnit plot with all of its false trails and suspects and twists is what's killing me--without the space to create suspense and tension, it comes across as a boring, overly detailed list (no matter how much I cut). I think another big issue is that the defacto "detective" character can't be the main protagonist for reasons having to do with casting/stars/the market. My producers have sent me a ton of written pitch samples that went well, but they're almost all for shows that focus on one or two protagonists, and NONE of them has a whodunnit throughline. Although my producers have done many ensemble and whodunnit series, for whatever reason they're unable to share written pitches for them. Has anyone ever pitched anything remotely like this successfully, or know anyone who has, or have any tips that come to mind? I've been trying to fight the feeling that my pitch is even more doomed than it already would be due to the state of our industry. Thank you!

EDIT: Reference shows are BIG LITTLE LIES (that's the main one) and WHITE LOTUS, with some BROADCHURCH, TWIN PEAKS, and THE KILLING thrown in.