I reckon all the methods you mentioned can improve your listening. A common efficient way is: listening without transcripts first, read the transcripts while listening second, and listening without transcripts finally.
However, everyone has their own best method, but the core is the amount of listening (more listening time and more materials are better). The method I mentioned above is a bad method for me, because I cannot do it for a long time. It's very boring for me.
If you are similar with me, I think good Chinese movies and dramas are good, because they are funny and will attract you to learn more. You don't need to listen any material repeatedly. Because Chinese is a very high-context style language. It has far more words with the same or similar pronunciation than most languages. So, materials should be a very large amount. In addition, similar Chinese sentences will appear again in other materials. Certain words or sentences are clearly more effective to hear in different contexts.
Therefore, if a method is interested for you (means you can do it for a very long time regularly) and you can easily try to listen and understand materials carefully, it's your best way to improve Chinese listening.
Pitfall: I think I should highlight some key point. A very common pitfall is 泛听, which means trying to listen a huge amount of all kinds of listening materials without carefulness. For example, if materials are too hard for you (like you can understand less then around 10% at your first listening), it will be useless. Because they are like noise for you. And if the difficulty of materials are good, but you just treat them as background sound without very little thinking, it's also useless.
If you have any further questions, feel free to ask me again.