How can one deal with the squandering of effort and time in summarizing books and writing lectures that benefit others without compensation, taking into account the noble Hadith: "Whoever is asked about knowledge and conceals it will be bridled on the Day of Resurrection with a bridle of fire," and the envy this causes?

There is no blame upon you for not sharing the results of your academic efforts with others. However, helping your brothers and colleagues, especially the diligent among them, is better and more virtuous, for it is a form of good deed and performing good. And Allah helps His servant as long as the servant is helping his brother.