Press Windows key + W first. If the Widgets panel opens, the taskbar icon is only hidden.
Right-click an empty area of the taskbar, select Taskbar settings, then under Taskbar items turn Widgets on. Microsoft’s guide: https://support.microsoft.com/en-us/windows/experience/personalization/stay-up-to-date-with-widgets-in-windows
If Widgets is missing from Settings or Windows + W does nothing, open Microsoft Store > Library > Get updates, and update Windows Web Experience Pack. Also install all Windows updates, then restart the PC. https://support.microsoft.com/en-us/windows/deployment/updates-lifecycle/how-to-update-the-windows-web-experience-pack