So likely dark matter is a different flavor of something already in the model. Dr. Mills' Hydrino theory presents hydrogen with the electron in a lower orbit that does not radiate as a candidate for dark matter. These states are stable like the ground state. Transition into or between hydrino states emit light in the UV or soft X-ray wavelengths that is not seen in optical telescopes.
There are many ways Mills claims to have experimentally verified the existence of hydrinos but the most obvious one is the faster than hydrogen transit through a gas chromatograph.
https://brilliantlightpower.com/atomic-theory/