It sounds like you might have seen a TV program from the early '00s titled "What The BLEEP Do We Know?" which made the claim that the wave function collapses based on conscious observation - i.e. a person is looking at it.
That's not true. That TV program was misrepresenting the science.
There is definitely a lot of very strange behavior at the quantum level. You mentioned a few: the double-slit experiment, delayed choice, spooky action at a distance.
But there's no evidence that consciousness is the cause.
My biggest criticism of simulation theory is that, when people who believe it want to make an argument that we ARE in a simulation, they point to things like quantum effects. But if I want to make an argument that we're NOT in a simulation, then no matter what argument I make, the people who believe we're in one always say, "well maybe that's simulated"
I mean, I could point to the exact same weirdness you just listed, and use it to argue that we're not in a simulation. But I've done that before and there's a 100% chance you're just gonna say, "well maybe the simulation is simulating that"