Why is extremely high pressure required to cause atomic nuclei to crash into one another in stats?

Extremely high pressure is required to cause atomic nuclei to collide because the positive charges of protons create a strong electrostatic repulsion between them, known as the Coulomb barrier. To overcome this barrier, nuclei must be brought very close together, which typically requires high kinetic energy that can be achieved under conditions of extreme pressure and temperature, such as those found in stellar cores. At these conditions, the thermal energy is sufficient to allow nuclei to overcome their repulsive forces, enabling nuclear fusion to occur.