You can use a PowerShell script to automate the download and installation of specific versions directly from Microsoft's servers: Using WinGet to Install Apps on Windows IoT Enterprise
If you are starting a new project today, is preferred. But if you maintain an existing UWP app, WinUI 2.8 is the last major stable release before the migration. microsoft.ui.xaml.2.8 appx download
Before installing Microsoft.UI.Xaml.2.8.appx, the system needs: You can use a PowerShell script to automate
The WindowsApps folder is hidden and protected by default. You may need to adjust permissions to view it. if you need to reinstall
No action needed. Or, if you need to reinstall, uninstall first:
file, you cannot always just double-click it. Use PowerShell for a clean installation. Stack Overflow Using WinGet to Install Apps on Windows IoT Enterprise