◇ Could this help me?
Yes. Debugging by telling an assistant to fix the broken part is the most common way people waste time with these tools, because a fix that cannot be evaluated is indistinguishable from a plausible rewrite. Asking for an outline of what the code does and how it diverges from the intended spec is a cheap way to convert an opaque codebase into something you can reason about, and it makes the next request specific enough to check. General practice.
Walk me through what this codebase actually does, at the level of a mental model rather than a file listing: the main components, what each one is responsible for, and how a request or event flows through them end to end. Then compare that against the intended behavior I describe below, and list every place where the code does something the spec never asked for, or fails to do something it did. Rank those gaps by how likely each one is to be the cause of the problem I am seeing, and do not change any code yet.