The occurence of redshift can be explained in conjunction with the refraction of light. In this case redshift isn’t Doppler shift. In fact, in special and general theory of relativity Einstein clearly ignored the refraction of light. Maybe Einstein was a genius, but I think he isn’t a genius in astronomy.
“The new alternative explanation is based on refraction phenomenon of optics. It predicts that as the ray passes through/near the star’s atmospheric
medium, it bends due to refraction phenomenon towards star core, like a ray bends while passing through a prism or water drop.”(R.C.Gupta,Professor,Institute of Engineering & Technology Lucknow, India)