How can I recover my photos and videos without having the iPhone or registered phone number?

If you "do not have the phone", you cannot recover any data – including photos – from it.

Your only hope of recovering the photos would be if you had already copied them elsewhere, e.g., by

• Synchronizing them to iCloud, using iCloud Photos
• Making iCloud backups that included photos, if you weren't using iCloud Photos
• Manually importing the photos to a computer

Then you might be able to recover them from that place. But without physical possession of the phone, you won't be recovering them from the phone itself.