The signing of the Treaty of Nebuchadnezzar seemed to give Siberia to Russia for free, but there were objective reasons at that time in the Qing Dynasty. At that time, Russia carried out foreign colonial expansion, often burning and looting in the outer Xing 'an Mountains, and established Jacques Castle and Nebuchadnezzar Castle at the confluence of the Nebuchadnezzar River and the Schleka River. The Qing army beat them away and came back, and beat them away and came back. In the end, the Russian army surrendered seriously and the country defeated by reason should get more benefits. However, at that time, the Junggar Ministry of Mongolia suddenly rebelled, and the Qing Dynasty was afraid that Junggar and Russia would jointly attack the Qing Dynasty. The Qing dynasty was unable to resist the joint attack from both sides. In desperation, we had to give up a part of the land that originally belonged to China. At that time, the main people living in Siberia were Mongolian tribes, who did not obey the control of the Qing Dynasty. The Qing dynasty felt that this land was of little use, but it became a springboard for Russia to invade Northeast China and Mongolia because of cession.
As for firearms, in fact, at the beginning of the founding of the Qing Dynasty, Kangxi encouraged the research and development of firearms. The firearms of the Ming Dynasty successfully defeated the Qing army and suffered heavy losses. After the Qing Dynasty entered the customs, it used firearms to quell the rebellion and recover Taiwan Province Province. However, after the stability of the country, firearms became a hidden danger to the monarch. In the early days of the founding of the People's Republic of China, they were only used by the children of the Eight Banners, and the Han army was not allowed to use them. After the political stability in Kangxi, the development of gunpowder and firearms was restrained. He thinks Mongolian cavalry is stronger. As long as no one uses firearms, civil strife will not be too lethal, and it is actually conceited to ignore the development of other countries.
These two things made China bullied. No wonder everyone is angry, but nobody is perfect. Did Emperor Kangxi do well at that time? He won't care so much in the future, that's a problem for future generations.