Unfortunately, ApprovalMax does not know who created the Bills that get pulled from Dext because all Bills that are then created in ApprovalMax are in the same name as selected in the Receive from Dext Prepare step:
By default, or if no user was specifically selected, The Account Owner will be selected for that QuickBooks Online Organisation.
This means that the Account Owner, as the Requester, will be notified of all approvals, rejections and comments.