There’s an explanation for all of this behavior that we are measuring but saying that it’s something we can’t see but it’s there!! is objectively absurd.
It is much the same for dark matter/dark energy. Without the dark matter 'fudge factor' cosmic observations at galactic scales or above are broken. We've also when and by observation removed a number of things that this fudge factor cannot be. And yet in our observations this fudge factor keeps existing and is found groups like the bullet cluster, or in a small number of galaxies that appear to have no dark matter.
There is not a single reputable scientist that says they know what 'dark matter' is. Scientists know that there are knowledge holes that exist here. They do say it is measurable and that you the denier cannot handwave it away without bringing forth a better theory.