Why not start such a space online? IMHO chat is best for this. E.g. Slack or Discord. Or if you prefer open source solutions then Matrix, IRC, Mattermost or Z

Why not start such a space online? IMHO chat is best for this. E.g. Slack or Discord. Or if you prefer open source solutions then Matrix, IRC, Mattermost or Zulip. You will need a critical mass, so I would try to aim for around 400-800 members or so. (Usually most people lurk so I wouldn’t aim for a too low number.) Best of luck!