Right now, the traffic light buttons overlapped on my iPad app top corner on windows mode (full screen is fine).
How do I properly design my app to avoid the traffic light buttons? Detect that it is iPadOS 26?
How to avoid the traffic light buttons on iPad
You can't eliminate the traffic light but you can specify its style a bit.
In UIKit you can implement the UIWindowSceneDelegate method preferredWindowingControlStyle(for:) and return one of three styles.
I don't know the SwiftUI equivalent.