What is edge security?

When the security rails are deployed closer to the user, it is called Edge Security

Should I use VPC Service Controls?

Not so. These controls prevent data exfiltration from your network, but don't necessarily do 'edge' security.

Which service should I use then?

A global load balancer sits closest to the end user traffic. This is the service to start with. To protect an HTTPs load balancer, you need to use Cloud Armor.

What should I do with Cloud Armor?

You can define security policies within Cloud Armor to allow / disallow external traffic from users to the Load Balancer.