As a software engineer, I am on the other side of this argument. Previously, I worked with BAs to understand and implement customer requirements. The design of the application was collaborative, but generally unique.
Then, an ambitious BA sold its management as needed for UI / UX. It has only been power struggles ever since.
UI / UX guys are trying to boil an "app" on just screens. They know nothing about the data, the infrastructure, what it takes to build the backend and they have no development experience. They often overlook the features available in a mobile application compared to a website or desktop application. All they do, is draw screens and act as if it's "their" application, so they're the boss.
The last thing all creators need is not having any experience that prima donna tries to take care of.
My advice is as follows: you are a consultant. It's the job of the BA to define the requirements. It's the job of the software engineer to create a professional application. It is up to you to link these two elements with screen models that meet the requirements and the technical direction, without annoying you, if we do not agree with the beautiful images you have drawn .
Think of it this way: if the only way to get your solution is to go to management, you are an obstacle and not a member of the team who is committed to making a better product.