Divergent chart is not possible in workspace. Can you share your data request so that I can recommend the chart type.Also, if you have analytics integration with other BI tools, you can create the divergent bar chart there or you can create the chart in excel using Report Builder.  

Hi, Marketing channel visits should be same as Entry page URL (Custom variable). Entry page URL contains unspecified visits. Please check if you are excluding unspecified visits as a segment in your report  if not then check your entry url custom tracking. Visits are calculated on session level henc...