According to standard cosmology, smooth dark matter particle halos around galaxies are responsible for the flat rotation curves of galaxies as observed.
However, recent observations conclude that NO evenly spread dark matter particle halos are needed any more, if we account for all the visible mass in galaxies.
see: The Radial Acceleration Relation in Rotationally Supported Galaxies,
( Stacy McGaugh, Federico Lelli, Jim Schombert)
My alternative solution is,
that dark matter is the same as new physics black holes, first present after the black hole splitting big bang as dual BH systems ( also early Herbig Haro systems) to form early galaxies in between.
Those dual BHs which I would call Galaxy Anchor black holes. ( GABHs).
Later after the big bang BHs seem to have produced early Galaxies, new supernova black holes would be able to form smaller star systems in between by so called dual Stellar Anchor BHs.
As a consequence, Dark Matter is not evenly spread as dark matter particles in the halos of galaxies.
All the dark matter is concentrated around visible matter in clumps.
Clumpy Dark Matter around Dwarf Galaxies is supposed to be a support for such an alternative Black Hole theory according to the Quantum Function Follows Form theory.
See also: figure 18, stellar anchor black holes.
And: Dwarf Galaxies and their relation with Dark Matter based Galaxy Anchor Black Holes GABHs).
However we also need a New Physics Black Hole theory.
Electric Dark Matter Black Holes Outside and Inside Galaxies possibly related to the creation and contraction of a Cyclic Universe.
Birkeland - Alfven Current Circuits between two RF generated Plasma Balls in the laboratory and two new paradigm Black Holes in space.