Can we customize the field element or render our own custom element when rendering form using json schema in form-js
@Niklas_Kiefer might be able to answer this question.
Unfortunately, this is not 100% supported as of now.
But good news: we are currently working on bringing full support of custom form elements (also extending existing ones) into one of the next versions of form-js. Just follow this issue to get the current state: Support for custom elements · Issue #123 · bpmn-io/form-js · GitHub