On the whole, the Ming Dynasty was kind to Duo Yan Sanwei. In fact, the Ming court basically didn't have the idea of sweeping away Mongolia. Zhu Di's point of view was to drive it away, but looking at the actual practice of the Ming dynasty, it was to contain the Mongolian ministries and not to make them too powerful.
For the Mongolian ministries closest to the Ming Dynasty, the Ming Dynasty was mainly kind to them, and those in the distance were driven away. If the ability allowed, the Mongolian troops in the distance were moved inward or moved near the Ming border to restrain them. I specially appended the process of Taining Wei of Wuliangha (Duoyan Sanwei) from Zhu Di to the end of Ming Dynasty. Basically, it is similar to the state of vassal and tribute, and the Ming Dynasty also gave it favor and sealed the official.
About the attack on Wuliangha.
according to the records of Yongle. Because Wuliangha had contacts with Mongolian ministries before Zhu Di's third expedition to the North, if he was appointed as the garrison officer of the Ming Dynasty at that time, he could be judged as collaborating with the enemy. Because Arutai rebelled many times at that time, and even the Ming court thought that the latest rebellion was a direct rebellion. When Arutai heard of Zhu Di's personal expedition, he fled directly, and the attachment of Wuliangha was still in the local area, so the Ming army decided to cut it off, which was the main reason why Wuliangha was attacked.
for rebel troops, force is generally used. However, for ordinary people, Daming's attitude towards Mongols was basically to distribute living materials and give them living conditions, and Wuliangha's scattered army and the old, weak, women and children later surrendered to plead guilty were all forgiven.
Because Zhu Di's policy towards Mongolia is not extermination, it is attached to a certain extent, and it is placed not too far away from Daming Border Guard to a certain extent and controlled nearby. If Wuliangha was loyal to the Ming Dynasty, Zhu Di could use this part of his power to control or contain Wala and Tatar. There is no reason to attack. The reason for the attack is treason.
Many people say that Zhu Di was overjoyed. In fact, Zhu Di did a lot of big moves, such as building and river embankment, which were not completed in time to boast of his achievements, but were pragmatically carried out according to the construction period until Zhu Di died. It should be said that Zhu Di was a pragmatic emperor.