Russia joining NATO in good faith would change it for sure but would not make it obsolete.
Who would that alliance be (ostensibly) protecting themselves from? China? Taking that kind of stance (EDIT: against China) would not be in Russia’s interest.
You don't need military action to provoke. The West has been trying to incite regime change all over the region, Ukraine is a prime example.
It's not a national defense strategy, it is a national security one. They need to control the paths for gas exports to Europe to maintain Europe's reliance on them for heat in the winter. It makes them powerful.
If you look at national strategies for nations and territories, even beyond the time the current state has ruled, for every major or minor power throughout history, you'll find similar strategies because the underlying realities remain the same.
If Russia did not get an ex-KGB absolute monarch traumatized by the fall of the Berlin wall, the country could've joined NATO by now. Pretending that this particular made up "national defense strategy" is the only one possible, is just caving in to the Putin's propaganda.
Even if Russia for some dumb reason chooses to be perpetually against the West even after the fall of communism, it does not mean that the West automatically becomes interested in invading Russia either. Even in this case the "national defense strategy" is just a cover-up for the unprovoked aggression.