It’s important to be careful when identifying the meaning and purpose of a symbol, as they can often have multiple uses throughout the years.
Typically, the Egyptian Eye of Ra represented the destructive power of the sun, which nevertheless was one of the most important parts of Egyptian life. This is because it represented all life, since without the sun they would not be able to grow crops and live as a society.
It also represents truth and justice, and its power over nature (life) is seen in many places throughout Egyptian history. It was often used as a symbol of royal authority, along with the crook and flail.
The Eye of Ra was also believed to be able to see anything, which is why it was often placed above doorways or entrances in temples- so that no one could escape its watchful gaze.
Its destructive power can also be seen as a warning against evil deeds; if you did something wrong, then the Eye of Ra would see you and punish you.