There are so so many manga that have changed the way I see things, but one I've been revisiting lately is Pluto.
https://mangadex.org/title/1594/pluto
It's a rewrite of an old Astro Boy arc called The World's Greatest Robot, and it's about a series of human and robot murders. The storyline itself isn't that complex until the end, where Urasawa honestly loses me a little every time with the identity-ception, but the questions he raises and ponders over through the course of the events in Pluto are haunting.
I still think back occasionally to how weird some of these moments are. The robots act and feel the way humans do, yet deny themselves that humanity constantly. There's a moment where one of the robots needs to get in a bigger robot, and my expectation the whole time was that he would climb inside, like a human does with a mech but no. He just...removes his head. Like a flash drive...
The thought of his entire identity being inside of a small portable drive, and not trapped in a flesh body, somehow made him feel so fragile even though robot bodies are stronger than human ones.
The main character suffers from nightmares, which isn't supposed to happen because robots don't dream. So then, if robots don't dream, what's happening to his AI to make him behave this way?
There's just a lot of fun psychological and physical differences portrayed between robots and humans in a world where they've become visually almost indistinguishable. I'd recommend it strongly, but it is admittedly kind of a niche thing that doesn't appeal to mainstream manga readers.