From experience telling me that any non Japanese who answer the Japanese questions must be the wrong answers. However, 良い and 善い both are kanji, which originated from China. My answer to your question is: 良い and 善い is 100% identical to the Chinese 良 and 善. Without the explaination from the Japnese. Billions of Chinese people who can tell you the difference between these two simple words. Since you are learning Chinese too, it is better to ask the Chinese, they can give you a better explaination between these two words.

良い is used for "good" in general. Like in good person, good friend, good question, good feeling, good score, good day, or whatever good. 善い is used only for some behavior/person which is right and good in the view of morality and humanity. For example, you can write "Good Samaritan" as either 良きサマリア人 or 善きサマリア人 （「善き」is old way of writing「善い」, if you are concerned）. But you can write "good question" only as 良い質問, not 善い質問。