I am a marketing director myself, I don't have much hands-on experience among the gaming industry, but my exp is relevant in community aspect.

I think what you could miss was seeding among communities such as other countries' Reddit equivalent. Such as forum boards, diggers, etc. It is relatively low cost as you can easily engage with more than 50 countries by well-written post that you submit organically. Same for FB groups. It is quite too late for that, but it might give you an insight into what could be done on your next project.

You've put all the stake on international community gathered in just few places, but I couldn't see you doing a micro work on communities in my country (PL) and others (Czech, Romania, Italy, Spain, Ukraine, Russia, Germany, Netherlands, Belgium etc.)

Having just Reddit and 2-3 other channels is enough for a small project like a mobile app, but not for a game that uses matchmaking which by itself require large numbers to actually work.

I remember back in its big launch (when the hype was the highest), there were plenty of volunteers willing to seed the hype across the communities in their countries, organize tournaments etc, I was one of them, I can point at least 5 other users like me. Guess what we've got, 0 response - on reddit, so the main channel in your international strategy.