What is the best practice for headless (UI outside Appian) implementation in Appian

Hi,

We have the following requirement and would appreciate the community's support to suggest the best practice for achieving the same.

Business Requirement :

A process for loan is triggered in a branch (CRM system) where all the customer and loan related details are collected and then submitted to another department(Credit department) in the bank.

All the UI and process related to branch is implemented in CRM, whereas credit department UI is implemented in Appian(review of submitted application happens in credit department).

if any discrepancies are found in the application, credit department can send the application back to branch(CRM) and once corrected flow will continue in Appian.

This return to branch/ different roles within the branch can happen multiple times at various points during credit department review

Suggestion required on below approaches:

Approach 1:

In traditional BPM systems, we create a Dummy task in BPM to indicate the external system task(CRM), once this task is created, we capture the task ID and notify the external system about the impending task that needs to be actioned. --> Once external system completes the task , an API call is made along with the same task ID and using the CompleteTask function/ smart service we complete the dummy external task in BPM and flow moves forward

Approach 2:

As soon as the credit department selects to return the application to CRM, we capture the state of the process in DB via records and the terminate the process, and inform CRM about the impending external activity to be done. --> Once external activity is completed in CRM, a new instance of the same process is created via StartProcess API--> we check the state of the application in DB for the same application number and redirect the flow to that particular step post external activity

Now, which one of the above mentioned approaches is best suitable for my requirement (Consider that fact that entire process is not a long running process and there might be a maximum of 2000 instances created in a day in Appian for all process of bank combined together), please suggest the same with pros and cons?

Also, If there is any other better approach, please suggest the same

Thanks in Advance

Suhas