Here is a site with a way to un/re-install the Store...
https://www.maketecheasier.com/windows-store-not-working-fix/
Windows Store Not Working? Here’s How to Fix it
The section entitled "Reinstall the Windows Store" hopefully fixes it.
Note: The site sounds smart, but I know nothing (bad or good) about any downloads or links that are there (or anywhere else). Also, I never did try that reinstall procedure myself.