Is there any way to do custom visualizations, specifically a radar chart?
Hi arubawayne,
Currently, it is not possible to create custom visualizations such as a radar chart in Quick Sight.
Hi arubawayne,
Thanks for reaching out. We are planning to launch Radar charts in late Q4 2022.
My boss is looking forward to adding that feature 
Radar charts is now GA! Kindly give it and try an let us know your feedback
Blog - Visualize multivariate data using a radar chart in Amazon QuickSight | AWS Big Data Blog
Thanks for great work!