In order to hide hover cards for inactive apps in taskbar of Windows 11, go to Settings > Personalization > Taskbar > Taskbar behaviors > Uncheck “Show hover cards for inactive and pinned taskbar apps ...
To show smaller app icons in the Taskbar, use these steps: (Option 1) Select the "Always" option in the "Show smaller taskbar buttons" setting to show smaller icons. (Option 2) Select the "When ...