I built a full WinUI app with no visual editor, just XAML and code. The layout was entirely in my head. Now I do the same with terminal UIs on Linux, pure code with fluent builders. Once you internalize the layout model, a visual editor mostly slows you down. Code-first gives you full control, clean diffs, and composability. That said, for complex layouts you still need to run and visually review, no one gets nested grids pixel-perfect from memory alone.