If you get deep into the details of orbital mechanics you would find that the orbits of planets and moons do change ever so slightly over time. The rotation of the Earth is slowing because of tidal effects. We usually neglect these changes as they are so small they do not effect the orbiting of a new satellite. nothing about cosmology is self contradict. Your understanding of cosmology is so superficial that you cannot begin to begin to see how it fits together. If you truly want to understand cosmology, quit watching YouTube and enroll in a class at your local community college. If you are truly serious about this, as you claim to be, then do some serious research by actually taking a class.
Scientism has replaced experiments with theories and is atheistic. How they get away with constructing irrational theories is amazing. Cosmology looks more and more like the theory of evolution where explanations are taken as facts rather than imaginative speculation and data is not subject to falsification and other possible explanations.
--Dave