I do believe Putin's stated reasons, yes. The reason I believe them is because Russia has consistently berated NATO, and the U.S. in particular for its role in breaking its word concerning not expanding NATO east of Germany. This is hardly news, but some have only recently come to realize this. A quick internet search found the following article on the subject:
When Washington Assured Russia NATO Would Not Expand | The American Conservative
Plenty of evidence that some U.S. scholars and diplomats suspected what would happen because of NATO's expansion:
US gov’t knew NATO expansion to Ukraine would force Russia to intervene | multipolarista.com
And then there's the Donbass citizens themselves. I personally believe their plight was more important than NATO's expansion. As mentioned in my previous post to you, I made a thread that I believe does a great job of laying out the evidence of how Ukraine's treatment of citizens in the Donbass region led directly to Russia putting boots on the ground in Ukraine.
It seems to me that as a Putin sympathizer [snip]
My focus in regards to the Ukraine war has always been on the arguments of the opposing sides. I don't agree with all of Putin's policies, but there is plenty of evidence that when it comes to Ukraine, the west has played very dirty with eastern Ukrainians. Russia tried for 8 years to find a diplomatic solution after what amounted to a coup aided and abetted by the U.S. 8 years ago, but at last decided that the only way to resolve the tragedy there was militarily.