The problem is that no one has ever demonstrated that there is a boundary. There are lots of claims for non-naturalistic effects (some of which you have made here), but no definitive "boundary". In fact there are many non-naturalistic claims that clearly inject into the realm of the natural world in demonstrably false ways.
I think the boundary has been demonstrated. For example despite saying that consciousness is an epiphenomena from the physical brain it only correlates consciousness to physical processes. It doesn't explain the nature of the experience itself and where it originates from. It only assumes it originates from the physical brain because thats all it can explain things by.
So if consciousness (the Force) is some beyond brain force science has crossed the line by attributing consciousness to the physical thus dismissing something that transcends the physical.
Let's be clear here. The "existing standard theory" that is being "accommodated" is *GRAVITY*. That "accommodation" is at the margins: vacuum energy, poorly interacting matter, long range modifications to the known form of gravity, etc.
Dark matter and dark energy are very well established astronomically. Astronomers and observational cosmologists have put significant restraints on the properties of each, but the theory hasn't quite caught up to them. (Or particle experiments.) It's kind of like Kepler's laws of planetary motion. Kepler worked out the relations to the motions of the planets, but he did not have a fundamental theory to explain them. The first theory to properly do that was Newton's some decades later and then Einstein's a few centuries later did an even better job. (And that may not be the final theory of gravity, but I'm not holding my breath for a "better" replacement.)
Since we already have a phenomenon called "consciousness" it is best not to induce confusion by overloading the names. Let's just call it "The Force".
(Oh, I guess you already did.)
But seriously, no that is not "just as speculative" it is drastically more speculative. The main dark energy model is a cosmological constant. Something so "new and speculative" that Einstein included it in his equations to avoid the collapse of the Universe. (The expansion wouldn't be discovered for another decade.) It had no bearing on anything but the stability/expansion of spacetime. It is an incredibly simple model and it has been undergoing testing for ~25 years.
Consciousness as "the force" has much more speculative problems as consciousness has *ONLY* been detected in Earth animals and nowhere else. Might there be living beings elsewhere in the Universe, sure probably so, but we have no evidence for them. And you don't really have a mechanism, just some Sunday afternoon noodling.
Some ideas make the Force prevade everything. At the fundemental level the electron as a rudimentary form and its grades upwards to more complex configurations. This seems to make sense in that some pioneers of QM said Mind was inherently in the electron and with QM experiments of the oberserver effect such as QBism.
Now you want it to also be dark matter? Oh boy.
Among the many problems that could be found with this the only place where consciousness is known to exist is the very place where we don't have any evidence of impact from dark matter or dark energy: Earth.
But if the Force is fundemental then it prevades everything.
Nothing (and I mean Nothing) about the known properties of the Galaxy and Universe that dark matter and dark energy are constructed to explain have even the slightest impact on the properties of our Solar system, planet, or life on it. None.
Yes and the Force at the very basic level may have no influence and just be sort of static but only activated at certain thresholds or states. We know this from experiments with psychodelics, NDE, Meditation, remote viewing ect. Or it may be that its information itself when combined in certain formulations gives rise to some form of the Force or different levels of the Force. As some of the pioneers of QM mention even the Electron has elements of Mind in it.
I say this because it seems to make sense as far as the data goes. Mind or Consciousness is non spacial or time restrained. It seems to be some sort of force where we can tap into and experience certain states which others can also do sometimes this has more force to influence things. In other words science only deals with the quantified aspect of reality. It leaves the scientists and subject out of the picture.
But to have a theory of everything we have to include the subject, conscious experience and how that fits into the equation. It seems
'reality with and without the Force' are two different things with destinct phenomena. So it makes sense as some physicists have proposed that the Force can influence things in some way, the oberservers choice influences reality.
If the Force is beyond physical brain then its fundemnetal and not just in humans but everywhere to varying degrees. Like other forces it can be tapped into and used to influence things.
We see glimpses of this in psychology, how human choices and perspectives change and influence outcomes of behaviour or mental states which are powerful. They seem to transcend, sorry extend beyond the limits of mechanical processes of chemicals and electrical signals like a robot. This phenomena is real and seems to speak of a deeper aspect of reality that cannot be understood through the science method.
These ideas like Math, Information, the Participatory Universe Principle, QBism, Panpsychicism, the Mental Universe Theory ect are attempts to fit the conscious subject into what constitutes reality.
The proposed "mind stuff" would need to interact with flesh, so why can't we detect it?
We can by when the flesh reacts and responds to conscious experience. Like needing food for energy the body reacts, insulin levels drop ect. But the feeling of hunger is on another plane. Its a experiential phenomena. Why should we feel hungry when we need food. Why should we feel awe during a sunset.
We can even conjure these experiences into being without the flesh part of the body provoking this and then this effects our physical boddies the other way around. These experiences are not in the mechanical processes themselves but our bodies do react when we have conscious experience.
In fact the power of their experiences can change the world. But they cannot be explained by purely as you say interactions with the flesh. They transcend that type of process and cause and effect. Yet they are just as real and change change reality. Whatever we want to call it, a new force, field or some unknown invisible phenomena its real in the world and cannot be explained in fact will never be explained by material science.
Since you are fond of speculating, let me try a bit: The scientists who run into these "odd" behaviors (particularly in QM) have a strong tendency to use supernaturalist language to describe them because of their prior supernatural pre-conditioning either through direct indoctrination or cultural absorption. Perhaps eventually, we'll get better at explaining these things.
I don't know. I mean I know that happens but it seems more and more mainstream science is going that way. They are not religious but atheist scientists. It seems that areas like QM naturally lead that way. But its not just physics. Its happening across the board like with evolution and the role of Mind, of conscious choices, free will, agency and teleology in evolution. Usually under evolutionary psychology or inheritence beyond genes such as culture or epigenetics.