This extension is inspired by XamlFormatter from DannOh which I used for Visual Studio 2017 and 2019.
Unlike XAML Styler this extension formats XAML documents line by line without encoding to preserve the original string. This means that the formatter only indents the lines without reordering elements inline or between lines.
In the new category "Format XAML" you can disable the formatting on save and change other settings.
You can add a shortcut to the command in the Tools menu.