While I understand the need for limiting the discussion here to "Using Kotlin to build Android applications" (and I deleted my previous message - I'm sorry), in my experience, "Android United" and "Android Chat" are almost dead. I still get more help in the #android-dev IRC channel on libera.chat. StackOverflow is way more useful than all those sources together, even if the kind of interaction is different from a chat.
I'll try the Discord server, in future.