Help please ! Split Brep Problem

I need help with something that seems relatively simple but I’ve been trying for 2 days, I simply need to cut my louvers that are coming out of a bend in the horizontal plane to separate them by floor, I’ve already tried split brep, split with brep, and partition and nothing, could someone help me?

Without your GH file and geometry :question: I don’t think so.

3. Attach minimal versions of all the relevant files