I use quite a few custom visualizations from the gallery - https://app.powerbi.com/visuals/. Often times these visualizations get updated an

Using some of the visuals is quite complex, yet they are basically undocumented besides a paragraph on the Custom Visuals page. Advanced Viz is the key area of weakness for PBI vs other mature solutions eg Tableau. Please put more effort into documenting, supporting and improving Custom Visuals.