Kingmakers Discord and community
The official Kingmakers Discord is at discord.gg/kingmakers, the invite the studio uses in its Steam announcements. For answers from the developers themselves, the Steam discussion forum is where the game director’s public replies can be read.

Official channels
Where the developers actually answer
Paul Fisch, the game director, posts on the Steam forum with a moderator badge. Most of the specific answers on this site, about consoles, Steam Deck, the engine and the playtest, come from his replies there rather than from announcements. A community manager account from tinyBuild posts the formal news. The most useful of those replies, grouped by topic, are in the Kingmakers Q&A.
If you want something answered, that forum is the most reliable place to ask. If you want playtest news first, request access on Steam, as explained on the Kingmakers playtest page.
The studio does not link a subreddit from its store page, website or announcements, so any Kingmakers subreddit is a fan community rather than an official one. Be careful which one you find: the name is shared with a book series and with Pathfinder: Kingmaker, a different game entirely.
A note on fake servers and downloads
Nothing official sells the game yet, and the only pre-release access is the Steam playtest. A Discord server or social account offering a download, key or early access in exchange for anything is not the studio. Why people ask whether the game is real at all is covered on what happened to Kingmakers, and the director’s answers to the scam threads on is Kingmakers real. The real ways to get in early are on how to play Kingmakers now, and the full list of official posts is on the Kingmakers announcement timeline.