Even if I wanted a Windows-specific UI, I still wouldn't choose WinUI 3. You can ignore it.

At my day job, I choose Windows Forms with Blazor mixed in. That's old reliable Win32 tech + modern web tech, without any modern Windows tech mixed in.

Win32 is absolutely the best GUI system, you get the most clean, performant and easy-to-use results.

I wish Microsoft just sticked to Win32 instead of reinventing the wheel with worse solutions.