Quailman84
I can see where you are coming from with the idea that you could trigger those neural changes through some other process. It's an interesting idea, and I wonder if it could be true in practice somehow. Regardless, I'd still argue that you are manipulating the brain in one way or another to create a firsthand experience of seeing the color red. If you can explain redness fully in terms of physical systems and processes, then somebody having that firsthand experience for the first time shouldn't be thinking "oh, so that's what it is like to actually see red."
If these are purely physical processes, then that knowledge should have come along with your complete knowledge of all of physics. You should also know what it is like to have experiences that your brain doesn't have the hardware for, like a bat's experience of echolocation. It seems like an unfairly high bar to clear; how could you understand an experience without having it firsthand? But if you are committed to believing that conscious experience is a physical thing, then I think you are also committed to believing that it can be fully described in physical terms. Physicalists do have arguments that try to explain how you could pass that bar in theory or dodge the commitment altogether, but personally I think those arguments are pretty weak.
If you ask me, there is nothing short of direct firsthand experience that will allow you to understand what it is like to see the color red.
Here's some further reading on that argument, if you're interested: https://iep.utm.edu/know-arg/
Just because something isn't physical doesn't mean that it is mystical or magical; it is just a different kind of Stuff. The idea that only physical things exist is intuitively pretty compelling to me, but I've found arguments to the contrary to be much more convincing.