There are two ways to pass Chapter 4:

1. Recover one painting, which is worth 40 million.
2. Recover both two paintings, which are worth 80 million.

The easiest way is to recover both paintings. You can achieve this by obtaining every heart of He Xiaomeng in the previous chapters, from the prologue to Chapter 4.

After you have obtained all of He Xiaomeng's hearts from every available path, during the scene where the main character argues with Liao Siyang, the Secret Guardian of He Xiaomeng (referred to as the Yellow Man in the game) will give you 2 paintings. However, if you haven't collected enough of He Xiaomeng's hearts, you will only receive 1 painting. (Even if you doesnt have any He Xiaomeng heart, you will get killed lmao)

After obtaining the 2 paintings, during the boat scene when talking to Shi Daqiang, tell him that you have recovered 80 million, and the scene will pass.

There is actually other method (refer to Number 1) where you only get 1 painting, but it's a bit complicated. I also forgot how I managed to pass Chapter 4 with only 1 painting.

Further discuss at comment section