How to prevent noise downstairs?

Discuss the noise problem with your neighbors. If you can't solve it, ask the property manager.

Stick a layer of sound insulation felt on the floor first, and then stick a layer of sound insulation and shock absorption cotton to reduce the noise coming from under the floor.

Then stick the soundproof cotton on the noisy wall.

The windows are also soundproof.

If these four points are done, there will be basically no noise.