Yes arrays are supported.
For generating configuration UI using JSON Forms I usually use this side here: https://jsonforms-editor.netlify.app/
In this editor you can generate your JSON Schema and UI Schema and as well have directly a preview option. For preview there are two kind of renderers. REACT and Angular. In Edge we are using the Angular one. When using the different previews you will realize that REACT and Angular in some cases behave differently. One example is when having an Array. Your UI is as expected rendered in REACT but not in Angular.
When using Angular you need to additional provide a layout when using arrays and inserting the elements to it. Which for REACT the layout is not required.