Just to be clear, you are dismissing the words of the guy who actually was in the room when some of these assurances were given.
You may find the accounts from two Ambassadors presented in this write-up interesting: https://transatlanticrelations.org/wp-content/uploads/2019/1...
Here's the direct quote from Ambassador Braithwaite's letter. Braithwaite was UK’s Ambassador to the Soviet Union and Russia until 1992.
The assurances Russians point to the following:
Assurances given in 1990:
• James Baker, US Secretary of State, 9 February 1990: “We
consider that the consultations and discussions in the framework of the 2+4 mechanism should give a guarantee that the
reunification of Germany will not lead to the enlargement of
NATO’s military organization to the East”;
• Helmut Kohl. German Chancellor, 10 February 1990: “We
consider that NATO should not enlarge its sphere of activity.”
Assurances given in 1991:
• John Major. British Prime Minister, Speaking to Defence
Minister Yazov, 5 March 1991: “He did not himself foresee
circumstances now or in the future where East European
countries would become members of NATO;
• Douglas Hurd, British Foreign Secretary, speaking to Foreign Minister Bessmertnykh, 26 March 1991: “[T]here were
no plans in NATO to include the countries of Eastern and
Central Europe in NATO in one form or another;”
• Francois Mitterrand, speaking to Mikhail Gorbachev, 6 May
1991: “Each of the [Eastern European] countries I have
mentioned will seek to ensure its security by concluding separate agreements. With whom? With NATO, of course. ... I
am convinced that is not the right way forward for Europe.”
This was, of course, a prediction, not an assurance.
[Author’s note: recently declassified material published by the National Security Archive contains some additional references to
similar “assurances.’]
This factual record has not been successfully challenged in the
West. The remarks by Major and Hurd are confirmed by British
records. I was present on both occasions.