Update: It now takes a few seconds to propagate new WireGuard keys and internal static IP-addresses to all servers.
In the latest Mullvad App (Linux, macOS and Android beta) you can manually rotate WireGuard keys and internal static IP-addresses.
The rotation will take a few seconds to propagates to all servers.
Settings, Advanced, WireGuard Key and press Regenerate key.
Settings, WireGuard Key and press Replace key.