@Sletty Good! You're asking the right questions.
Very, very simply: "physical reality" has precisely the same ontological status as last night's dream.
If you want to claim that last night's dream was "real" and "objective", go ahead. But my guess is, that's far from what you're trying to do here. You're trying to cling to duality.
Objective/subjective is a duality which must collapse.
Science is utterly inadequate to lead you to Truth. But it's good for manipulating the dream.
All of existence is a farce. That's the essence of enlightenment. Yes, you need to come to terms with that. And you ain't gonna like it at first.
Whatever you've experienced with Vipassana practice so far, is like 0.0000001% of the radicalness of Absolute Infinity. It will destroy the floor beneath your feet. Life as you know it will cease. You will be dead from that point on.
Maybe try a strong psychedelic to blast all your resistances away. You are too stuck in your own logic and it doesn't sound like you will make it out without serious help.
BTW, if you're doing Vipassana properly, you should be clearly seeing that "brain" is just a concept. What is this nonsense abstraction called "brain"? It doesn't hold water. There is no such thing in your direct experience. It's just a dogma. Look very closely.

Realize that PMO is the highest correlative sign of depression besides maybe literally attempting suicide. That is, more than almost anything else, the more you PMO the more depressed you are. So, as you do anything to stop PMO, you end up doing something to prevent depression. 
Seriously, you need to understand this because its important: STOP PMO AND YOU STOP MOST OF DEPRESSION.
PMO might not cause depression, or it might not be depression, but it's one of the biggest check engine lights you might have. 
So, set stopping PMO as a high priority and don't let anything get in the way of that.
Moreover, you can't follow actualized.org if you don't take responsibility for your life. Period.
But letting PMO stop you shows a major sign of irresponsibility. You're letting your dick take over your life. It's pathetic. I mean, how do you expect to change your life and change the world if you can't even take responsibility for your own dick?
So, make a commitment. Envision the life that’s possible and then envision what happens when you don’t take action. Then, when urges pop up, just find new shit to do with yourself. 
Also check out Improvement Pill's work on the topic on YouTube. He has a whole thing called the Tamed course that's fantastic.
Also Check out the book the 4 tendencies. 

Materialism states that from matter arises something called a human and from the material human there somehow arises consciousness. We can explore the material world with our consciousness or knowing of it, and find objective truths from reality. So matter first, then consciousness.
 
But this is ass backwards.
 
How do you know matter?
With consciousness of it: a perception of a "material" object.
What is a perception of matter?
Its a phenomena in consciousness, that could be further divided as a sight, sound, taste etc. Something about something is known: known in consciousness. When you truly trace it down honestly, everything you think you know, everything you perceive is just known. So if every piece of knowledge about this so called world is ultimately ALWAYS a perception, everything IS a perception. So what is a perception? It IS consciousness, its not separate from it. Perceptions don't appear separate from consciousness, consciousness does not appear separate from perceptions, thus there is no sense in talk about them as separate things. They are the same thing and "happen" simultaneously, "consciousness" and "perception" are just convenient words, as we can in fact separate them verbally. Alan Watts loves to talk about this. But words are not reality, reality is reality,
All this is deeply counter intuitive, because it truly _feels_ that there is an outside world with properties, that is not you, but it just does not stand when honestly investigated. The rabbit hole here goes very deep:
There is/are no physical:
space world humans body organs parents children physical anything, you name it To say that matter exists as its own reality, is like (Im maybe too much of a Ruber Spira fanboy. Rubert <3 please someone burst my bubble) saying that an image on a screen has more reality than the TV. It gives matter more reality than it deserves.  Table, TV, chair, dragon, what ever. They are all on the same line: a perception.
But wait, there is more
When you have an enlightenment experience, you realize that everything is consciousness/perception. Point to the thing you call your "self" in your direct experience. It must be there, because it has been with you all your life, right? All you can do is point to a story about who you are. What ever you tell me you are, is not really who you are, that is what you tell yourself to be. By talking to me about yourself is actually claiming that you are a sentence, and that's rather ridiculous. And so is your story of yourself. Now stay silent. That is what you really are: a knowing.
In the realization of no self, lies a deep mind fuck. Yes, you find out the most important and relevant truth for you: who you are, but you do not get any information about _what_ you are actually perceiving. Like holy fuck what is happening here? A DOG and a CAR? There are perceptions, sure, but can someone plese tell me what is this thing called reality I'm perceiving?
 
That is what I call a cry for materialism
 
I agree, none of the content of your perceptions make any god damn "sense", but when you have an enlightenment experience, you realize that it really, really, REALLY does not matter what it is, because that whole quest for meaning and "base" for everything rises from the materialistic paradigm, and you know better now.The "stuff" you would eagerly call matter, that you perceive, is made of itself, that is, perception.
The notion of "stuff made from itself" rises an immediate scientifically minded rejection/objection that goes like this:
"But i can investigate what underlies things! When I investigate a matryoshka doll, I find another doll. Surely I can run this process on everything, and ultimately reality itself! Saying that stuff is made of itself is just giving up!"
 
This is just another way of saying
"I will juggle perceptions until I arrive at a non-perceptual truth!"
 
To say that there is a material world, that you are perceiving, is jumping to conclusions based on your intuition, not on careful investigation of what is true unconditional of your assumptions. Remember, that you can't deny that perceptions of _something_ is all you REALLY have of the "world". When you hear a cat barking, or a lion mooing, you assume based on the sound that there is this particular source for it. You must realize that every time you make a connection like this, a claim about the reality that is outside from your direct experience, you are making an assumption. We don't like assumptions here on Truth city.
We could put a cat in a box a million times and hear its bark, and take it out, and hear a ba- okay that joke died, hear a meow outside of the box the cat now visible, and a million times you would say that the cat is meowing in the box, but that is just not your direct experience, and will never be, unless you directly see or otherwise perceive the cat meowing. It's ridiculously counter intuitive, I know, but run trough the logic for yourself and see for yourself that when materialism and non-materialism are put in a cage, the matter gets eaten.
I'm on the same boat as @Leo Gura on this, that the bottom line for materialism is that there is absolutely zero evidence for it, because there never could be. Personally, I sure as hell feel like there is matter, but yeah. It's just a feeling. Or dare I say it: a perception of it