How to live on the first floor without letting neighbors see privacy and how to avoid noise interference?

If the window is not directly in the living room, but on the balcony connected with the living room, you can make a glass sliding door at the junction of the balcony and the living room. Or a cheap bamboo curtain door that can be pulled. Any door will do.

Poor sound insulation is very troublesome. If you can't afford to move home, you'd better install sound-proof doors and windows and decorate sound-proof boards with good quality. If it's short rent, buy an industrial earplug and take it with you when you sleep. Such a building is not suitable for long-term living. If you can move, you might as well live somewhere else.

I live in such a building. People in the building interfere with each other because of poor sound insulation, including all kinds of noises in life at night. Later, after a long period of lack of sleep, they quarreled about the sound insulation problem, and neighbors retaliated with each other with their voices, even to the point of framing and killing people. Because living in such a place for a long time, people who don't get enough sleep will have neurasthenia and even get mental illness.

If you can get a sliding door, you can actually get a glass soundproof door at home, which can also isolate one of the rooms from the outside world.