If someone is struggling with it still, think about the moon.

On the surface of the moon, the sun looks basically like from the earth, small disk in the sky.

From ~~lunar~~ solar eclipses we know that just from 300.000km away (on earth) the moon looks just as big as the sun.

Now imagine you travel just a couple million km further away, the moon will look smaller and smaller, while the sun stays almost the same (as the distance to the moon will be 10 times bigger and the distance to the sun will increase by like 2%). If you are just 3 million km away from earth the moon will be a small-ish dot in front of the sun (it would cover about 1% of the suns disk, if my math maths out).

For context, the moon and mercury are quite comparable in size.