Currently it is possible to choose among two options as default view for accounts with a the Default Account View Veeva Setting. The two options are the Timeline view or the Classic view.
Since 19R1 update there is a new tab which is the "Overview" tab that contains the Account overview pannels. These were included in the Timeline view in previous versions and it was possible to default this view by defaulting the timeline view.
After this update, since it is in a new tab, it is not possible anymore to default the account view to the overview pannels.
The suggestion, therefore, is to make it possible to select the Overview tab as a default account view (for example by adding another possible value to the Default Account View Veeva Setting).