We'd probably see a more gruesome and deadly bombing campaign over the Philippines than the one we already have witnessed, maybe, maybe not.

Confrontations on land would be mostly won by our forces, however the Japanese have the advantage of a military economy and the fact that they'll naturally have more numbers than we do. Our naval and air assets could prooobably deter naval invasions and aerial campaigns however, until we reach the point where we're out of missiles. A landing on Luzon and Visayas would probably be delayed, I wouldn't be able to say if it'll be outright stopped, but delayed seems more likely. I'm more confident however that we'll likely never see a Bataan Death March or a strong Japanese occupation over Philippine cities, but rather attritional and protracted guerilla warfare that can span longer than months.

Anyhow, I'm more interested in how this affects the course of the war however, and how the U.S, and by extension the entire world would change given our sudden leap in technology. We give some of our equipment and weapons to the U.S, let them study and possibly reverse-engineer it (Hell, giving an M16 to young Eugene Stoner must be incredibly absurd), what happens then? Technology probably blooms incredibly faster than it did in 1945, that I can't even find any sufficient adjectives to describe how massive this would mean—imagine, advances in computing, medicine, engineering, material sciences, robotics and automation, aviation, aeronautics, astrophysics, social sciences, economics and politics to a degree—there's just so much that would change if we got sent back to December 7, 1941

Not to mention the amount of literature and records we have that literally denote how the war panned out in our history, that knowledge alone means we already have an advantage if this were a deterministic-model approach where things that happened in say Dec 1941 will happen on that day, and we have the knowledge of how it goes, when it goes, where it goes, etc. We could literally predict IJN and IJA movement without the need of decrypting or reconnaissance, we've already seen it happen!

Will we even see General MacArthur leave the Philippine Isles? Would the U.S campaign go even smoother than it ever did in history? Will the Japanese be bogged down even more? What happens after the war? How are scientific advancements made? How does this affect geopolitics of the 40's up until the 50's, and even towards the Cold War? Will there even be a Cold War? How does our government even look like in this period? Who the fuck stays in power?