Because of data caching, you can only see data until yesterday on the main dashboard.
Via Today Tab, however, you can see all your data for the current day. To view the Today Tab for the desired dashboard, you need to:
Go to the dashboard for which you want to access Today Tab
Click on the Today Tab button (see picture below)
IMPORTANT NOTE: Widgets from your dashboard won't be automatically copied to your Today Tab within that dashboard. If you want to track certain metrics in real-time, you need to go to Today Tab and add them manually, as you would regular widgets within your dashboard.
You can use the same widgets as those on the main dashboard, but the best practice is to use only widgets that update daily.
Search Console, SEMrush and some other data sources have a slight delay of a few days, so there’s no reason to add them to the Today tab.