(1) Oops, I clicked get & got...

So, apparently you've got to have the Store app to use the store site -- sheesh! Sorry about that!
(2) Are you signed into a Microsoft Account or at least into an Administrator account that is linked to one? The Store probably doesn't work otherwise.
(3) As I posted on page 14, 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.
(4) If that fails, try an upgrade/repair install. Make a Win 10 Installation USB drive here...
https://www.microsoft.com/en-us/software-download/windows10
Download Windows 10 -- currently, this is version 21H1
You download the MediaCreationTool21H1.exe, plug in an 8 GB/so USB drive, & double-click the tool to run. It will create bootable media that could be used to clean install Windows, if the repair-install is ineffective. But for the repair-install, just open the Installation USB drive in File Explorer, & click Setup.exe. It is a repair, if your computer is already 21H1; otherwise, it is an upgrade to 21H1. See your current version at "START, Settings, System, About". It should keep everything intact -- apps, files & settings.
If you get upgraded (& things seem worse), you may undo it at "START, Settings, Update & Security, Recovery, Get Started (under 'Go back to previous version of Windows 10'"...

But it lasts only 10 days. Also, it isn't available after a repair (just after an upgrade).
So -- make a Windows system image backup first. That lasts forever as a means to restore Windows to before the upgrade or repair. Want instructions? You should be doing that anyway.