Seeing a massive battle between multiple armies and having sauron show up with the ring is ... super lazy storytelling? Huh? It has nothing to do with Gandalf

Seeing a massive battle between multiple armies and having sauron show up with the ring is ... super lazy storytelling? Huh? It has nothing to do with Gandalf. Also, Gandalf doesn't know and he confirms it indirectly through research which is also shown in the movie....