A little update. The ARN-AMS flight tomorrow was cancelled early this afternoon. I immediately got on the whatsapp chat (no response since). Tried calling KLM, but only reached a busy signal. After a couple of hours I called KLM again and was accepted into the line, and got through to an agent after 15-20 minutes. They managed to get me on Thai flights ARN-BKK and BKK-KIX, which are perfect. Apart from having to wait for physical checkin to select seat, it all worked out great! Kudos to KLM once I got hold of them!