This is a semantic excursion. I'm bailing myself out of trouble by qualifying my statement as "probably" factual somehow, since it's not trivial to back such a concept.
Semantic in the sense that the word "environment" is a loaded term.
I'll offer this much: photons are particles. As particles, we know them to be part-time resident constituents of massive objects. That massive objects are representative of large quantities of energy trapped and oscillating in bounded standing waveforms.
We know that the empty vacuum of space really is mostly void, but also that a lot of photons (particles) are still traversing the void quite a bit.
So, space/time, while an empty void, where phenomena transit or conduct themselves theough said empty medium, is still an environment with varying concentrations of activity.
If an neutron manages to be ejected from a supernova, and is directed toward our solar syatem, and is influenced to fall toward the sun, but, miraculously passes straight through the sun, without colliding with any other particles, only to travel onward toward the center of the galaxy, landing in a supermassive black hole some millennia from now, what would you say about the environment this neutron experienced as it fortuitously passed through the center of the sun, without experiencing any collisions?
Would to rob it of all the other qualities, and just label it space and time? Or would you refer to it as an environment, with activity transpiring, in addition to be also being a realm of space and time?
Dark matter has yet to be defined as anything other than an observed effect on the behavior of matter. Something (and indeed a thing, if anything, ergo matter) we think is probably there.
Being a theoretical hypothesis, formed to explain observations, it remains a side-effect of accounting and inference, and has not been located directly.
Show me why you believe it is a thing. Show me where you have found it. Tell me why it isn't actually matter.
That does not invalidate the concept. Gravity has not been found to be an incidental phenomenon measurable for anything other than matter's accumulation.
In the observable universe (regardless of theories and expressions penned on paper) gravitational forces are always induced by massive material objects, including the remnant artifacts of deceased stars. To suggest otherwise is to walrus the conversation.
A good tan! Get some sun, bro!