Hi Gantry,
I am not a professional in games, not even do I know much about websites, forums etc, I can only offer my humble view as an average player

There are only two games for which I have ever looked up anything online:
Carcassonne and Pokemon Go
For Carcassonne I ended up here and for Pokemon Go I ended up on Reddit (The SilphRoad), both brought me also on Discord.
Why these two?
- they are active (nothing worse than a "dead" forum)
- they provide quality information
- they provide the possibility to exchange with other players /get in contact with other players
- they are friendly, welcoming and organised
- they react instantly to the latest news OR EVEN BETTER they bring to my attention the latest news
The last point seems to be of more importance than the others. I feel that any forum that has "a direct line" to the author of the game/the game company has already an advantage because players will get the impression that they might get the newest information here first....
In your situation, you are comfortable, because you ARE the author/game company. So wherever you will get active, this will be the place where people will go.
So for me it looks like you chould first focus on already existing platforms with many players in order to launch your game and get attention and get people talk about it. After some time, when you see which platform works best for your game, you can maybe focus on that one and attract the various players there.
Only after that I would think about starting something myself (if this is even necessary or if you feel that the fanbase is big enough and you don't like the existing platform)...
Anyway, I wish you all the best of luck with this project!
