@Vlada_Karban_ELITE_T
It’s a question of finding an audience that’s receptive your solicitation.
Your first post “would like to list all Zwift users. Ability to filter users by nationality.” suggests that you’d like to reach out to everyone on Zwift in countries X, Y and Z. That strikes me as spammy, and of course HQ will not allow that.
You are allowed to make your pitch on this forum - we occasionally see posts along those lines in the Racing board. I just don’t see a lot of followup activity on such discussions, so I’m not sure how effective this approach is.
The specific Facebook group I suggested is very active, and its members are there for the express purpose of racing. It’s a focused audience, and one that would be receptive to your pitch. Of these three options, I felt this one will be most targeted and therefore the most effective use of your time.