Great question. Just my personal opinion:
So let's take a step back to establish some rules for how the unseen works in our world.
1 - One of the fundamental elements of quantum mechanics is that everything we think "exists" is a wave that collapses into a particle when observed, and that probabilities are how it all works. However you're reading these words, quantum tunneling is how some part of the memory works on that device, which is not about physical electron gates allowing electrons through, it's about making the probability of the electrons being on one side or another collapse to zero.
2 - Magic relies on intent to happen. So intent of any sort has a way of shaping our world in a statistically significant way. This is well-documented across various forms of tests, from people in a lab affecting random number generators, to studies of prayer, to the placebo effect. Magic is harnessing our ability to use intent of our own, and of others, to change outcomes at a macro scale. Coupled with the fact that probabilities are fundamental to how the mundane world works, the connection is clear of an area of cause and mild effect. Gravity also has mild effects on us, and we understand how its effects manifest, but we don't actually understand how it works - through what medium it propagates, how gravitational waves arise from mass. So it's not like magic is a singular unknown spooky woo-woo thing in an otherwise fully understood universe.
3 - If intent has the power to change outcomes, it has to be both 1) a form of energy, and 2) have a medium through which it works. We have access to this medium and energy via our bodies, and this is a weak effect that because it doesn't consistently interact with our mundane 3+1 dimensions, makes it impossible to confirm using electromagnetic tests. So, in short, our emotions, our love, our hate, our fear, produce energy in an unseen plane of existence.
4 - Non-corporeal sentient and non-sentient entities do seem to exist, with evidence pointing to a poorly understood set of rules around them that make testing with existing equipment hard to do. Ghosts, UFOs, etc. Many people here work with unseen (and can be seen if they really want) entities that exchange energies for intent. This is no different than feeding a horse before going for a ride, or giving a child candy for good behavior. First, you as the magic practitioner have to tame the horse or explain to the kid how they earn candy. Sometimes it's you being offered candy in exchange for behavior. It's a two-way street.
4.5 - My personal super-not scientific theory is that non-corporeal entities exist mainly in the dimension where dark matter exists, because dark matter and dark energy have no entropy. These entities exist as something with mass but that can't do anything until they transverse a data plane with no mass in order to incarnate as a physical being in our 3+1D space. So they can possess our bodies the same way a primary soul/spirit would, and when not relying on the engine of a body, they alternative method to experience entropy is when they dip into our 3+1D space, which is what they need our energy to accomplish.
And I'll add that I think that fae, house elves, demons, grey aliens, and everything else in the "paranormal entities" bucket are non-corporeal entities of the same general categories. To me, the Greys are demons that found a modern niche that propagates their ability to collect that delicious emotional energy they love.
So then - Simulation theory simply adds that somewhere a sentient group of entities put us in this situation. Nothing about what I've already said above changes, other than some committee set rules for us, and these are how the rules work. Magic is small order effects at best. It's a boost, or I think buff is the gamer term for it. Controllers would not need to bother with magic because they are the ones that defined how magic even works, so their flick of the wrist would necessarily be more powerful than all the forces we know of in the universe. They can extinguish our sun, turn off gravity, or unbond the nuclei of atoms at will, which is more than magic or science can do.
If there are "Controllers" then are they among us? Not likely, and I don't think any non-corporeal entities are at the level of controllers. Controllers can put the rules on hold. They would operate on the level of omnipotent gods to us, not even the demiurge gods of myth and religion.