Playwright has limited support for testing desktop applications. According to the Playwright documentation, it supports automating applications based on Electron or Microsoft Edge WebView2. And in the GitHub issue #10927, people are talking automating applications based on the Chromium Embedded Framework (CEF) with mixed success.

At it's core, Playwright is using the Chrome DevTools Protocol (CDP) for automating browser. So if you have a desktop app that can be automated via CDP, you will likely be able to test it with Playwright. But if you are planning to test a desktop application built with some other desktop framework (such as WinUI, UWP, WPF, React Native, Qt, etc.), you should should probably look into other options.