unable to use the DFF value in the Mapping Set for approval routing

Currently, we are using Manage Requisition Approvals, where multiple approval rules, approval groups, supervisory routing, and job-level routing are configured together. As a result, it is difficult to determine why a particular approver was selected, and maintaining these approval rules has become increasingly complex. Our objective is to use Mapping Set-based approvals by deriving the Requester Department through standard attributes, similar to the logic available in Manage Requisition Approvals. However, we are unable to identify a standard attribute or table that provides the Requester Department for Mapping Set configuration.

we also tried using a Requisition DFF to store the Requester Department. However, this approach does not work as expected. Initially, the Department is auto-populated based on the default requester. However, if the preparer changes the requester on the requisition, the Department DFF is not automatically refreshed with the new requester's department. Because of this limitation, we are unable to use the DFF value in the Mapping Set for approval routing. Could any one please confirm whether there is any standard attribute or database source that exposes the Requester Department for use in Mapping Set approvals, similar to