I think this experience really depends on what Discord server you are in - all of mine are 10-30 people scattered across the globe, and conversations frequently happen asynchronously, including people chiming in hours or days later. I’m not in big servers so can’t speak to that experience.

WRT participation in EN fandom as a non-native speaker, I am specifically referring to likes, kudos, discord emoji reacts, and retweets/reblogs as forms of engagement that don’t require writing in EN. I totally agree with you that DW is a better medium for written communication without an intense sense of urgency, and I am glad it serves you in this purpose.