If Putin truly seeks to divide EU/NATO, permanently, he may, ultimately, have to follow through on his suggestions of a nuclear exchange. He might need to target one NATO member for annihilation and see if all others are willing to sacrifice themselves in order to retaliate. If it comes to this, I’d recommend one, particularly Imperialistic island in the northern Atlantic! I doubt any of the continental nations would be in any hurry to invoke article 5 to defend the empire.
The EU/NATO are already divided from the beginning.
NATO:
Who remembers the big problems that NATO had to face in relation to France during the Cold War? There were many.
In the invasion of Iraq, who doesn't remember that only Spain and the UK vassal supported the Americans with the motion that was rejected by the UN?
Speaking of Spain, this nation only joined the organization in 1982, I would say that Franco did not trust NATO countries very much. In Spain's own popular referendum on the country's NATO membership, over 43% voted against, with over 56% in favour, nearly half of the population, and that was still in 1986 at the height of the Cold War.
Gibraltrar is still the source of enormous disaffection between the UK vassal and Spain.
Vassal UK also sends Navy ships to Jersey as post-Brexit fishing dispute. Regularly sends fishing vessels.
Note: Amazing the participation of each problem the UK is involved.
EU:
When Turkey began to "rebel" from NATO by negotiating with Putin, the EU wanted to sanction Turkey. For a given motion to be implemented, all countries in the bloc have to pass the vote, so it needs to be a unanimous decision. Hungary voted against the motion aimed at sanctioning the Turks, Hungarians have good relations with Turkey.
The American vassal - UK, could not stand the bloc's regulation and asked for resignation, Brexit clearly showed a rupture between the EU countries and NATO itself.
The Greek debt crisis has also split the bloc. Many countries did not want to pay the Greek public debt with the effect of paying for an irresponsibility of Greek politicians, Germany ended up taking on the Greek problem because many citizens of other countries did not want to take on the Greek default problem, in fact not even the Germans wanted to , the German politicians who took over under public scrutiny, but the German politicians knew that if they did not help the Greeks, the economic bloc would enter into crisis not only because of interdependence, but also because of the inertia in not helping the member of the bloc, which could cause suspicions and future ruptures. A real trojan horse.
The problem of Catalonia's independence also divides the bloc. Between others.
It is even possible for Marine Le Pen/Éric Zemmour to win because of Macron's disastrous government, that would be a huge strategic gain for Putin.