Hello, Welcome to Microsoft Community.
Thanks for your feedback, Based on your description, it seems like you're facing an issue with the installation of Windows App Runtime.
This appears to be the installer for Windows App SDK. I suggest you try the installation package from the following page to see if it completes the installation.
https://learn.microsoft.com/en-us/windows/apps/windows-app-sdk/downloads
Just click the "Download the latest X64 stable installer" button on the page to download it.
If there is an error message during the installation process, please provide us with a complete screenshot of the error message so that we can give you further advice.
Lugoo Bei | Microsoft Community Support Specialist