Lambda-CDM explains very well the observations at large scales.
We have tested this theory with different observables — with the cosmic microwave background, with galaxy clustering, with the Lyman-alpha forest. And all of them are in agreement with what is predicted by the Lambda-CDM standard model for cosmology. By construction, different models of dark matter agree well with observations at large scales. They have to — otherwise we wouldn’t use them.
But small scales have not been measured so well, and that’s why they provide fertile ground for testing different scenarios.
— Read on www.quantamagazine.org/harvard-cosmologist-cora-dvorkin-dreams-in-dark-matter-20201105/