Add each client with fixed posting days for Social media, GMB and Blog (for example Social on Mon, Wed, Fri). Every scheduled day shows as a slot and stays red until it is marked Posted.
A slot counts as missed after the end of its posting day in the client's own time zone (IST for India clients, the client's US zone for USA clients). Each client can have Social media, GMB and Blog tracks, each with its own posting days. Every slot is red until someone marks it Posted. Overdue slots also count in the alert at the top.