Not supported by data. There is plenty observational evidence that the redshift is due to cosmic expansion, e.g. galaxy surface brightness evolution, CMB, time dilation, the list goes on.

The website you link poses a number of unsubstantiated claims without any answer to the numerous problems it raises.

Then he links to this hilarious notebook; https://colab.research.google.com/drive/1K1qoUFvqZp1fWbpcKJW...

I don't mean to sound rude but this doesn't look like the work of someone who has spend any considerable amount of time actually studying the Universe.