Putin has agreed in principle to a summit with Biden.
He has not secured his objective with his power play negotiation, and it is backfiring, and he knows that.
If he capitulates, he will lose face and strength, and become vulnerable in Russia.
If he invades and causes mass casualties his economy will sink like a stone into North Korea territory, and he will strengthen Nato and solidify their purpose and position.
He must find an exit ramp before it is too late and that might be through partial or whole implementation of the Minsk agreements.