Dark matter is:

As I read in the press, we have found a great percentage of dark matter.
Astronomers have suceeded in seeing the shadows of filaments in the
light of the CMB.

https://www.sciencealert.com/astrono...visible-matter
quote
So both teams of researchers relied on something called the
Sunyaev-Zel'dovich effect, a phenomenon that causes photons left over
from the glow of the Big Bang to scatter into slightly higher energies
as they pass through the electrons in the gases surrounding galaxy
clusters
end quote

This cosmic web becomes thicker. That is good news, maybe all of it is
just that:

"Dark matter" that we just doesn't seem able to see easily. But not
anything exotic. Just that: normal matter.

There are also filaments between the stars, this time detected by
gravitational effects in the light of background stars.

The whole thing looks like a connected web. And that web could be very
massive.

jacob