Which voltage regulator should I choose to power STM32 + 4G module + GPS with low consumption when they're in stand by?
AMS1117 has a quiescent current consumption of 5mA typical, 11mA maximum under conditions similar to yours. So that current is wasted 24/7. It is, however, a remarkably cheap regulator and thus is found everywhere. If you walk through the streets in Huaqiangbei there is a non-zero chance you might find some stuck to the bottom of your shoes.
That 5-11mA range is not a particularly low current, you can probably find a CMOS regulator that has more like 1 or 2uA of quiescent consumption. It will likely cost more.
Follow the recommendations in the datasheet as far as input and output capacitors near the regulator to the letter. And calculate the worst-case thermal conditions to ensure a reliable design. Skip either of those and you may have a very bad day.