First of all, you mentioned Chen Wenjie, the illegitimate child of Qianlong. He is just a character in a film and television work. His source is a TV series called Nine-year-old County Grandfather. He was born when a man named Chen Qinglian visited incognito. Although he is said to be his illegitimate child, his blood is still flowing on him, and Gan Long is still taking care of him.

First of all, I think he should look for people who knew about it at that time, that is, Gan Long's confidant, and ask them to provide Chen Wenjie with relative living expenses to help him learn and grow. And sent someone to secretly protect Chen Wenjie, don't let others find the existence of Chen Wenjie, protect him from being killed. During the crisis in Chen Wenjie, Gan Long also sent his men to point out Chen Wenjie's identity and let Chen Wenjie escape.

Thanks to the care given to him by Qianlong, Chen Wenjie's life has developed better. He has been smart and studious since childhood. When he learned his identity, he didn't want to find Gan Long and get his proper identity. Instead, he learned from his heart silently and didn't want to embarrass his father. So he took part in the imperial examination, made great achievements, and finally became the champion. Moreover, there is no one else in this champion, and it is given by Gan Long. Visible, it is precisely because Chen Wenjie is the illegitimate child of Ganlong that Ganlong can have compassion and give Chen Wenjie such a title of top scholar.

However, because Chen Wenjie is not a real person in history, there is also a lack of relevant records in history. So I can only answer your question according to the plot in the TV series and my own imagination.