Yeah quantum physics by itself is not proof of a simulation or anything. It's just how it works reminds me so much of how you would build a video game/simulated world.
I mean all these concepts of something that can be in a totally random or unpredictable state, until you "observe" it...well isn't that exactly how you build a video game? A frame buffer? You can think of atoms as the pixels or graphic primitives of a video game. How would an NPC in a game perceive/interact with a pixel? It would be beyond comprehension. It only becomes something perceptible when the pixel is used to render something that can be understood.
Not sure comparing the structure of the universe (mind numbingly complex) with the design of video games (extremely simple by comparison) is necessarily the right thing to do... especially give that if you're introducing the notion of quantum physics into the equation, you can't then compare that to anything designed to operate within the framework of general relativity.
For instance, your comparison of pixels to atoms rather breaks down once you realise there are more atoms contained within the head of a pin than there are stars in the entire galaxy. I doubt NVidia will ever produce a graphics card capable of rendering that many pixels. Also, pixels are effectively joined together to create a video game asset. Due to the electromagnetic force, most atoms never actually touch one another. It's their repulsion that allows separate matter to exist.
Experiments like the double slit don't support any claims to us being in a simulation, but they can theoretically support the notion of multiple realities, if you can see past the Copenhagen interpretation (the forcing of choice upon a quantum particle from the act of observation).
The main thing to bear in mind is that an atom is 99.9999999999% empty, which means that on a quantum level, we can't exist in a simulation, because there's virtually nothing there to simulate.