Used Google charts this week Mainly - pie chart - stacked column chart pie chart is here:
https://developers.google.com/chart/interactive/docs/gallery/piechart
several modifications can be done several options that can be configured it uses svg
https://en.wikipedia.org/wiki/Scalable_Vector_Graphics
its all about svg parent element then grapics "g" element under g there can be text, rect, etc. elements specifying options is most easy its not easy to know what is the best option to use though Advanced Usage can help
https://developers.google.com/chart/interactive/docs/customizing_charts
or, the main chart page can help for example, pie chart main page is at
https://developers.google.com/chart/interactive/docs/gallery/piechart
its possible to use css to change the elements display style or even use the javascript to find elements change the style/ display properties, or the elements themselves under the svg we can create svg elements too. however slight change in DOM functions createElement becomes createElementNS when creating an svg element it's easy if we can find the options for it or, we can do css & javascript this is definitely not simple 3 hours of work for complex charts, however its possible to do anywhere from 3 to 7 days of time if you are new to google charts