As blocking access to the store app isn’t available through GPO in 10 Pro,
This is an option to keep your users from installing store apps.
There’s a firewall rule allowing outbound access for the store app, this PowerShell command will switch it to block the app
Get-NetFirewallRule -DisplayGroup ‘Store’ | Set-NetFirewallRule -Action Block
The app will still be available, but will only display this:
To revert to a working store app, run this one:
Get-NetFirewallRule -DisplayGroup ‘Store’ | Set-NetFirewallRule -Action Allow