I tried to convert the startEvent form from the Generated Task Forms to the Camunda Forms because I wanted to use the select/checkbox function. But when I call the API process-definition/key/{{key}}/submit-form, it cannot work with the Camunda Forms, there is no validation although some required fields are missing. But it works well with the Generic Forms.
And then I tried to use the Camunda Platform, it can work with the Start Process and the UI form will validate the error.