Is the Chat app not for you? Here's how to remove it from Windows 11.

[Windows Central]

If you don't care about the new Chat app on Windows 11, you can remove it quite easily, and here's how.
On Windows 11, alongside the redesigned experience, you will also notice that the new Taskbar has a purple button, which is the icon for the new Chat app.
The experience is actually part of the consumer version of Microsoft Teams that comes integrated by default on Windows 11. The idea with this integration is to bring an easy-to-use interface to quickly connect with family and friends with video calls and text messages without downloading another application.

Full story from the WindowsCentral blog...