It can sometimes be difficult to tell whether a spot is dust or dead pixel (https://devicefixes.com/blog/what-is-a-dead-pixel/) damage on a display. Dust is typically diffuse and sometimes moves a little during cleaning, and tends to lie on the screen surface. However, a dead pixel remains in the same exact location, and will become more noticeable when the background is bright. Before testing the screen with colors, gently clean the display with a microfiber cloth. If the dot doesn't change after cleaning, then the dot problem is more likely to be a pixel problem than dust.