Putin gave an "explicit warning that Russia perceived NATO's eastward expansion as a threat to its national security" as early as 2007 in his Munich speech.
And as a result (in combination with other factors) Ukraine's NATO aspirations were effectively halted by 2009. Simply put - some hawks in the U.S. wanted it, but it never got traction in Europe - not even after the initial invasion in 2014. In other words - in regard to the NATO-Ukraine question Putin had by that time already achieved a successful, non-violent containment strategy. But ultimately he opted for the full-scale invasion in 2022 anyway.
Why? Because it was never his real reason in the first place.
The Russo-Ukrainian war began in 2014 with the ouster of Yanukovych, who was pro-Russia and opposed closer ties with the EU.
First, it wasn't an "ouster" - he fled to escape likely imminent charges of corruption and complicity in murder. Second - if you really believe that whatever happens in the internal politics of one country is a "reason for", or can "provoke" another country into launching a full-scale invasion -- then I don't know what to tell you.