You are probably correct. The US has many ways to get around a Congressional obstruction. Among other things it could “sell” them to Poland or the Czechs on an emergency basis. The Poles could then drive them to Ukraine.
They can sell them directly to Ukraine if the Secretary of State “certifies” that it is an “emergency” and in the National Security interest.
Except that the Poles , after dealing with the double dealing and demands, are willing to write off the Zelensky government. Nothing worse than a politician that won’t stay bought, or shows ingratitude to those who have supported him.