"the west" has made some mistakes, but I strongly disagree that it shares "guilt and blame in equal proportion as Putin." There are no excuses to justify invading a sovereign country unprovoked. It is a clear breach of international humanitarian law. The IJC agrees:
UN international court of justice orders Russia to halt invasion of Ukraine | Ukraine | The Guardian
NATO, and in particular the US was willing to find a "middle ground" however Russia refused to accept the proposals of the US and NATO. Putin demanded too much and was not willing to enter serious negotiations. A combination of harsh economic sanctions and a war that is not going very well for Russia, has made them interested in sanctions.
Russia insist on her "red lines", but so does NATO. I have not seen any "red lines" from NATO that I strongly disagree with. I cannot say the same for Russia's "red lines".