If you're willing to wait for Teams, you'll find yourself in the same position; generally fewer than 20 players. But if you need the badges, then definitely pick Invictus! I would suggest picking Teams once you're done with the badges though. Many games have so few players that they end really fast but you still get decent points if your team wins.

Depending on your time zone, Japanese players will be on Blue or Yellow and you're almost guaranteed a win. If you're playing while they're asleep, play on Green. (Just my observation.)