You could create the datastructure for your complex forms with inpersistent entities. When you open the page with that form, you need to create a new instance of the inpersistant entity which is then your helper object. Then everyhing on that form will be handled with the inpersistent entity. You will need to have a event like a Action button, which will trigger then a microflow and the action in the microflow will handle the data from the inpersistent object or objects to the right persistent objects.