9.0 Pie – Are there any shortcuts to adjust the brightness unintentionally on a Huawei Nova 3i (Android 9)

I try to help a visually impaired older person with his phone. She found that when the automatic brightness setting is turned on, the screen is too dark for her to see.

Without the automatic brightness enabled, it somehow manages to reduce the brightness by mistake. I wonder if there is a shortcut that reduces the brightness.