1) of course, but it is not something that the west and Ukraine could do on their own when Russia was starting a war in 2014.

2) That's incorrect. It wouldn't have stopped Putin but only given him more than Ukraine.

3) Probably had little impact on Russia's decision to start a war.

4) The same as (2). It wouldn't have stopped Putin but only encouraged him even more to subjugate Ukraine, if it didn't want to play by Russia's rules.

In other words, I don't think you have any suggestions that would have helped to avoid this war.