Method 1
This is the simplest way to remove the Copilot icon from the taskbar.
Open Taskbar Settings
Right-click on an empty space on the taskbar and select Taskbar settings.
Locate Copilot Toggle
Under Taskbar items, find Copilot (preview) and toggle it Off.
If you want to just hide copilot from taskbar, then right click on copilot icon and select "unpin from taskbar".
Outcome
The Copilot icon disappears immediately.
Warning: If the toggle is unavailable, check for pending updates via Settings → Windows Update. A restart often resolves such issues.