How to Pre-Populate Template B Fields from Template A?

Hello ManageEngine Community,

I'm using ServiceDesk Plus On-Demand and need assistance with template customization and data population.

Background:

Template A: A frequently used request template with fields used when creating follow-up requests.
Template B: A template for specific follow-up actions based on Template A.

Objective:

Enable users to create a new service request using Template B directly from an existing Template A request, with specific fields in Template B pre-populated based on data from Template A. This aims to streamline our workflow and reduce manual data entry errors.

Current Workflow:

A user creates a service request using Template A.
From within the Template A request, the user selects Action > Create Service Request and chooses Template B.
Desired Outcome: When selecting Template B, certain fields automatically populate with corresponding data from Template A before the user manually submits the new request.

Challenge:

I need to pre-populate Template B's form fields with data from Template A without programmatically creating the record (to avoid duplicate records and bypassing manual review). Essentially, when the user opens the Template B creation form from Template A, the relevant fields should already be filled, and the user can then submit the request manually.

What I've Tried:

Deluge Scripting: Extracted necessary fields from Template A using Deluge scripts but couldn't figure out how to integrate this data into Template B's form without programmatically creating a new record.
Custom Actions: Explored creating custom actions to transfer data but am unsure how to implement pre-filled forms without auto-creating Template B records.
URL Parameters: Investigated using URL parameters or DevTools methods to pass data between templates but haven't found a solution.

Assistance Needed:

How to Pre-Populate Fields: Guidance on passing data from Template A to Template B so that when a user initiates the creation of Template B from Template A, the desired fields in Template B are pre-filled.

Additional Information: