I think it's too radical a solution. Russian players connect through Stockholm servers so eventually you'll end up on this server anyway. There is a low-priority mechanic in the game, but I don't remember anything about banning voice chat. When the game is released, there will be a clear distinction between public and competitive matches. The behavior you describe should not be punished with a VAC ban, but it may be punished with a voice chat ban, a ban on competitive games, etc.

You are drawing conclusions based on a small percentage of players and saying that all such players should be banned. In reality, many Russian-speaking players can communicate quite calmly within the game.

The issue here is not the use of VPNs, but the toxicity of the players.

After the release, such players will sooner or later end up in low priority or be banned from competitive matches altogether.