Why do low pressure updraft and high pressure prevail in downdraft? From high pressure to low pressure again? I would appreciate it if you could be more detailed.

You need to know the direction of the airflow:

-Horizontal direction

Low pressure updraft and high pressure are common in downward flow-vertical direction.

The direction of horizontal airflow is from high pressure to low pressure. If the water flows downwards.

The vertical airflow direction will be influenced by the horizontal airflow:

The horizontal airflow merges into the low-pressure area, and the low-pressure air will form an upward airflow after accumulation.

The high-pressure airflow flows around, and the air loss needs to be supplemented by high-altitude air, thus forming a downward airflow.