Nato already has missiles and forces on Russia's borders and in the 70 odd years of the Nato alliance it has never attacked Russia. Claiming that Nato would suddenly be a threat to Russia, despite all the "threat" items you listed already being a reality, shows that any "Nato threat" is simply fiction.
Boris was not responsible for talks breaking down, regardless of any "tentative" agreement made, no peace agreement was reached and the gulf between what was discussed and what was not discussed being so wide that any actual peace agreement was a very long way off.
The failure of Putin to capture Kyiv and the discovery of mass grave war crimes perpetuated by Russian forces were the reason for talks to collapse.
