Hi and thanks for reaching out. My name is Bernard a Windows fan like you. I'll be happy to help you out today.
I understand the issue you have, there is nothing to worry I am here to help, upon checking the app, there are certain countries where the Disney plus app is not working and is available to download, I am positive that the developers are currently working on that, in addition, as an alternative, you can still install the app using Microsoft Edge by following the steps below:
Open the Disney plus website in Microsoft Edge: https://www.apps.disneyplus.com/
Then log in to your account
Select the browser menu ••• in the upper right corner of Edge.
Navigate to Apps and select Install this site as an app
Name the app Disney+ and hit Install.
Reference: https://www.windowscentral.com/how-install-disn...
It is under "INSTALL DISNEY+ THROUGH BROWSER"
Let me know how it goes and I hope that helps.
Bernard