I have a few questions about Steins;Gate that I would like answered.

No, this is just like Jiuzhen going to the past to deceive himself and save his assistant.

According to you, since the assistant has been saved and not dead, why does Jiuzhen Will he go back in time to save her?

However, the assistant continued to study the time machine without the knowledge of the past murderer, which led to the chaos of the world line. He died in another world line, and murderer induced his past self to avoid it. That world line, such an infinite loop, in fact, the dead are really dead, but in another world line