The expansion of the universe and the motion of galaxy clusters towards The Great Attractor are two different phenomena that occur on different scales and have different causes.
The expansion of the universe refers to the overall increase in the scale of space itself, causing galaxies and galaxy clusters to move away from each other on large scales. This expansion is driven by the property of space called dark energy. The expansion of the universe is happening everywhere and affects all galaxies.
On the other hand, the movement of galaxy clusters towards The Great Attractor is a result of gravitational interactions between galaxies and galaxy clusters. The Great Attractor is a gravitational anomaly located in the direction of the constellation Centaurus. It has a large gravitational pull that attracts nearby galaxy clusters towards it.
While the expansion of the universe is a global phenomenon affecting the large-scale structure of the cosmos, the motion of galaxy clusters towards The Great Attractor is a local effect driven by gravity. The scale of the motion towards The Great Attractor is typically smaller than the effects of the overall expansion of the universe.
Therefore, on large scales, the expansion of the universe dominates, leading to galaxies moving away from each other. However, on smaller scales influenced by local gravitational interactions, galaxy clusters can exhibit motion towards regions of higher gravitational attraction, such as The Great Attractor.