Chillverse lets you control how you appear to other players from Settings, with four options:
Online means you're visible to everyone and shown as active. Idle keeps you visible but marks you as away. Offline makes you appear offline to others even while you're using the app. Invisible goes a step further — other players can't search for you or add you to a game at all while you're set to invisible.
This is a manual setting you choose yourself, not something Chillverse decides automatically, so pick whichever level of visibility feels right for how you're using the app at the time.