The hidden treasure is not Christ. The field is the world. Christ is not hidden in the world. Lost people are the ones hidden in the world. Christ is not hidden in a field. He does not hide somewhere and expect us to go and find Him. Nor does the sinner find Christ and then hide Him again. The sinner doesn’t sell anything to buy the world (which the field represents), in order to gain Christ. The sinner must forsake the world to gain Christ. Furthermore, the sinner cannot buy Christ.
The sinner is therefore not the buyer of the field, nor is Christ the hidden treasure. Jesus is the buyer of the field, and saved people are the treasure for whose sake Christ bought the field.
The kingdom of heaven is what is hidden. That’s obvious from the post and the scripture. However, “unless a man is born again, he cannot see the kingdom...”