Use Discourse Hub.
On desktop, you can “install the site as an app” (on Edge, you’ll see a button for this on the right of the address bar, and you can then enable “Auto-start on device login”) and enable “Live Notifications”.
Still want a native app? That’s a request for Discourse, but while it’d probably take less RAM and start up smoother, I don’t think a native desktop app is feasible for them. But theoretically any third-party could make it.
Sorry @UMARismyname@Spcfork !
Actually, the mobile app has the forum. Account > Forum. This opens the forum in the app (how I usually use it).
You can open any links within it too, but it has to start with https://. (I access AMC and the Meta with this).