Make alert modals for critical actions highly visible to emphasize their importance. Otherwise, users might not realize how crucial the alert is and automatically dismiss it.

The color red is often used in UI to grab users' attention and convey importance and urgency. It immediately stands out to us because of the ways our eyes work — about 64% of the cones in our eyes are sensitive to red light wavelengths. So, use red to convey the importance of critical or urgent alerts. 

Another way to reinforce the importance of the message is by adding icons like the circle X mark, the exclamation point, or the sad emoji.