How to identify if a transaction has been initiated by a proxy (delegated user)

We have multiple custom approval rules for our assignment change transactions and in the current approval rules, we see if the transaction is initiated by our line managers or HR specialists and the approval route is based on the requestor.

When a line manager role is delegated to another user and if the proxy user initiates an assignment change, is there a way I can identify if the transaction has been initiated by a proxy (delegated user) within the approval rules?

For example, X is a line manager that delegates his line manager role to Y. When Y logs in and initiates a assignment change for X's direct report, the current approval rules which are written like this fails: