I use metabase for very simple charting and the pulse features. (which are awesome by the way team).
For Sankey Diagrams and most complex/ product focussed visualisations I use Airbnb Superset. It is now in Apache incubator meaning it will get more support and improvements over time too
Sankey diagrams are one of the key visualisation components of this but in general Superset doesn’t have the ease of use of Metabase and how data is broken down into questions instead of queries.