Thumpalumpacus
Major
Latvia and Estonia directly border Russia and so does the north tip of Norway, all NATO countries so I don't know where your "gentlemen's agreement" comes in. It would be a mistake for the west to say NOW to the bare-chested blubberhead that Ukraine will never join. He gets what he wants that way and can tell all of his people and his cronies that the invasion, er, sorry, "special military operation", was worth it.
No nation or group of nations should change its foreign policy to appease a bully. I'd thought this lesson got learned 80 years ago ....