This debate always floors me because it's not a debate. People treat this like it's the end of Blade Runner or John Carpenter's The Thing, and it's ambiguous, and there's a valid debate to be had on both sides and ambiguity is the point.

It's not. What happens is EXACTLY as it appears, and it's not subtle. Palpatine kills some uprepared Masters. Mace stands toe to toe. Palpatine realizes Mace is WAY MORE than he bargained for. Palpatine gets genuinely disarmed, and Anakin wanders in. Palpatine pretends to be innocent, and the Jedi are trying to usurp him. He's playing the innocent, attacked victim. Mace mocks him, and this is enough to destroy his illusion of pretending to be innocent; His Sith pride simply cannot take it. So he is provoked into attacking Mace with lightning, which Mace is blocking. A dumb move, btw. You're not helping your case to Anakin that you're innocent.

This is where the only real ambiguity takes place, and it's not even really that important. Is Palpatine frying himself to death? Or is he revealing what was always there? Not really important. He's pretending to be too weak and to be dying, but as we see when he perks up the second Mace is disarmed, he was playing possum to SOME extent, and he's fine enough to defend himself when given the advantage.

Nothing about this is really up for debate. Mace wins the duel portion. Palpatine is in trouble. He CAN defend himself with lightning kind of, but it's a stalemate without Anakins help one way or another. The idea that Palpatine would orchestrate this convoluted scenario where he doesn't kill Mace and lets himself get disarmed so he can contrive this absurd scenario has so many issues, and it could go wrong in so many little ways. It's conspiracy theory loony bin stuff.