iCloud Backup - Backup Total & Device Total Different

I recently upgraded my phone and am now receiving the message that I do not have enough cloud storage to back up my new device. When I go to iCloud Storage, the total storage for Backups shows 41.8GB, however, when I open the Backups folder I only see my iPad (8.9GB) and current iPhone 16 Pro Max (0GB) listed under the devices. I believe the backup for my old phone is still being stored in my iCloud storage, however, my previous phone doesn’t appear under devices to delete the backup. How do I resolve this so the correct backup amount is reflected in my iCloud?