The friend who notices you went quiet and checks in privately has more influence than anyone with followers.

Attention aimed at one person is worth far more than attention spread across a crowd. Noticing that somebody dropped out of the conversation takes care, and reaching out away from the group spares them explaining themselves in public. People remember that for years. It also means your voice carries with them long afterwards, without you ever trying to make it carry.

Think of somebody who has gone quiet lately and message them on their own rather than in the group chat. Ask something plain and leave room for a short answer. Do not make a point of having noticed.