"Gained a lot" or "I gained a lot" is the most straightforward and simple way to express this in Engpsh.
This expression is commonly used in Engpsh to describe a situation where a person has learned or acquired something of value. For example, a student might say "I gained a lot from attending that lecture" to express that they learned a lot from the lecture.
Here are some example sentences with their translations:
I gained a lot from reading this book. (我从阅读这本书中收获很大。)
Attending that conference was really beneficial, I gained a lot. (参加那次会议非常有益，我收获很大。)
Through this experience, I gained a lot of knowledge and skills. (通过这次经历，我收获了很多知识和技能。)