FWIW (which is not much), I was an astrophysicist whose research was Dark Energy, though I arrogate to myself no authority on this topic as frankly a lot of knowledge I used to possess on the topic has been replaced by knowledge of tedious programming APIs (meh...it's a living). My sense was that, perhaps owning to their colorful (colorless?) names, and because they diffused into popular culture more than other equally-important theories in other fields, Dark Matter and Dark Energy were presented to and apprehended by laypeople as "exotic". This invited speculation about these theories and even an urge to overturn them, especially where "exotic" was equated with "tendentious." But, by my lights these theories aren't very exotic. Dark Matter especially seems to me to be very consistent with the history of particle physics. Rutherford first proposed the existence of the neutron in 1920, but it wasn't observed directly until 1932. Pauli first proposed the existence of the neutrino in 1930, but it wasn't observed directly until 1956. Both are forms of "dark matter" and neutrinos were once a candidate for explaining flat rotation curves in galaxies and the "missing mass problem", until they were later excluded by observations of large scale structure. Dark Matter interacts with gravity strongly enough that its effects on astronomical and cosmological scales are pronounced, but it interacts with the other forces weakly enough that so far it hasn't been observed directly. So what?
"the nature of dark matter and dark energy"
I don't know anything about "the nature" of things. That sounds very philosophical to me.
"What are [the properties of Dark Matter and Dark Energy] aside from their effect on the large scale structure of the universe?"
I don't know. I also don't know why you're excluding (in the case of Dark Matter) its gravimetric effect on the large scale structure of the Universe. That seems like a pretty important property to me.
There is an alternate timeline where dark matter receives an extremely boring name like "inferred low luminosity particulate" and 100,000 very repetitive internet conversations never happen.
"the nature of dark matter and dark energy"
I don't know anything about "the nature" of things. That sounds very philosophical to me.
"What are [the properties of Dark Matter and Dark Energy] aside from their effect on the large scale structure of the universe?"
I don't know. I also don't know why you're excluding (in the case of Dark Matter) its gravimetric effect on the large scale structure of the Universe. That seems like a pretty important property to me.