We all know that’s the true end credits

This unfortunately is not an answer to your question but I remember watching Spider-Man 3 when it was broadcasting in my TV and it was going normally until the mirror scene. It showed the deleted Venom mirror jumpscare scene. Rest of the film went normally though I don't remember if the ending and end credits had any differences as those two parts of the film I always skipped for some reason. I just always thought that after Harry's death the film ends.

Watched this in the cinema when I was 9, this never played.

have you tried getting old movie recordings?