Please recommend a relaxing and pleasant novel with a modern setting.

I can only vaguely remember that the main character obtained a system and possessed a girl. The girl was very good at playing the piano and taught the main character how to play the piano. The second one seemed to be a cat, and the third one was a programmer's sister (who seemed to be disabled in both legs) teaching the protagonist programming. The rest were forgotten.
He asked for a book and presented it with gold coins.

Answer 1

I'll recommend a book called "Sign in for 10,000 Years, I Become a System". This was a book based on a city setting. It told the story of an ordinary person who was bound by the system. The system could provide him with all kinds of cultivation techniques, secret manuals, and props. He also became stronger and stronger, becoming an omnipotent existence. It was very relaxing and interesting, suitable for readers who wanted to relax. I hope you like this fairy's recommendation. Muah ~😗