I understand your frustration, and I need to be direct with you: what you're trying to accomplish isn't going to work the way you expect.
The core issue is that Excel's "Allow Edit Ranges" feature relies on Windows NTFS security and local Active Directory authentication. When your Excel file is stored in SharePoint, this feature cannot connect to your company's Active Directory domain because it's attempting to use a local Windows security model that doesn't function with cloud-hosted files. This is why you only see "DIN***" (your local machine) and cannot access your AD domain.
Unfortunately, there is no native way to use Active Directory authentication for range-level permissions in SharePoint-hosted Excel files through the "Allow Edit Ranges" feature. Microsoft has not built this integration.
Here are your actual options:
Option 1: Work with the file locally
Download the file to a network drive connected to your domain, set up "Allow Edit Ranges" with AD users there, then upload it back to SharePoint. Be aware that these permissions may not persist reliably in the cloud environment.
Option 2: Use password-based protection
Use Excel's "Protect Sheet" feature with different passwords for different ranges. This isn't Active Directory-integrated, but it does provide range-level control. You would need to share passwords with appropriate users separately.
Option 3: Accept SharePoint's limitations
Use SharePoint's file-level permissions to control who can access and edit the entire file. This integrates properly with Active Directory but doesn't provide the cell-level or range-level granularity you're looking for.
Option 4: Consider alternative solutions
Explore Power Apps, custom SharePoint solutions, or third-party tools designed for granular permissions in cloud-hosted Excel files.
The straightforward reality: SharePoint and Excel's cloud integration simply doesn't support Active Directory-authenticated range-level permissions. This is a genuine limitation of the platform, not a configuration issue you can resolve.