It’s in the best interest of the US to let bygones be bygones and forge closer diplomatic and trade relationships with Vietnam in the face of China’s increased aggressiveness militarily and economically in the region. Although Vietnam will likely remain close to China, the US will now be on stronger footing by deepening partnerships in the region thanks to Biden's diplomacy.
Biden is being deceived in his attempt to look tough on China. He's making deals with Vietnam's ruling Communist regime while they continue to maintain tight relations with Beijing and even Moscow. This is good for Vietnam's public diplomacy but ultimately makes the US look weaker.