Success using a VPN does not indicate server issues. All a VPN does is change the route your data takes - it still goes to the same place though. It is like taking a detour around an accident or construction on a road.
If you have issues with an Activision game you will need to work with Activision on it. Blizzard does not make their games and can’t fix their games or servers.
You can read the pinned thread here for explanations and links.