Server List loading 1% of servers, can't connect to 99% others

Game mode: Online
Problem: Bug
Region: Europe

The in-game Server List takes ages to load a single server (usually an American or Asian one), and if i let it go for 15-20 minutes, it will ususally end up finding 5-10 servers to which i can connect just fine… Yes, my filters are default (Internet / All Combat / All everything).
I then tried the Steam Server List, and there i can see hundreds+ of servers, but whenever i try to connect to them, the game opens, and i get an “Failed to join game” error.
The very same happens when i try to Direct Connect to servers my friends play on, or found on browser lists.

Steps on how to reproduce issue:

  1. Buy the game
  2. Start the game
  3. Try to join an Online server

I have verified files, reinstalled the game, deleted the logs and database, reinstalled the game, uninstalled BattleEye, reinstalled BattleEye, reinstalled the game…

The game works flawlessly in Singleplayer / Co-Op, i’m on a computer with an up-to-date Windows 7, with Firewall and Defender OFF, Steam ports routed, never have i ever encountered anything like this.

Any hint or lead is appreciated!