Ancient emperors got married early and gave birth to children early. Jiaqing came to power only after Qianlong's death, when he was middle-aged.
The achievements of Kangxi, Yongzheng and Qianlong are so remarkable that people ignore their shortcomings. So everyone feels that the Qing Dynasty seems to have been crossed by Jiaqing, and everything is Jiaqing's problem.
But in fact, Emperor Qianlong was a spendthrift, so the state treasury was in deficit after his death. In addition, in Qianlong's later years, corruption in the Qing Dynasty was serious. Although Jiaqing copied the home of Xiao Shenyang, the corrupt system already exists. Jiaqing did not fundamentally and systematically solve the problem of corruption, and local corruption is still serious.
Many people are dissatisfied with Ganlong's literary inquisition in his later years. Although Jiaqing was abolished, there were still local people who revolted because of corruption. At this time, the Qing Dynasty was already unstable.
Jiaqing is actually a little closed-minded. Although opium was prevented from entering China in large quantities, it also lost the opportunity to learn about other people's advanced technology.
Jiaqing wants to be a good emperor. He is really demanding of himself and trying to change, but he doesn't have the ability to make bold innovations. Coupled with the mess left by Qianlong, he can only solve it from the surface, regardless of the fundamental problem.
I don't think he has any talent in politics. Unlike Kangxi, who succeeded to the throne at the age of 8, there was no plan for the nine sons of Yongzheng to seize the office. He just passed on his position, and he did it honestly. For example, small Shenyang was greedy, so he imitated small Shenyang, but he never thought about how to deal with local corrupt officials.
I think he is poor. He can have real power as soon as possible, and it is estimated that more schools will not be so miserable.