Which of the several fields of water conservancy and hydropower civil engineering is more promising, and which one is relatively easier to take the exam?

Registered civil engineers (water conservancy and hydropower engineering) are selected according to five professional directions: water conservancy and hydropower engineering planning, hydraulic structure, water conservancy and hydropower engineering geology, water conservancy and hydropower engineering immigration, and water conservancy and hydropower engineering soil and water conservation. I am also taking the exam, and I am taking the exam to be a geotechnical engineer. Majors in water conservancy and hydropower do not necessarily have to apply for the above one! Geotechnical is a good choice, and I heard it is a relatively easy one to take the exam. Our senior brothers and sisters here are all in the field of water and electricity, but they all took the geotechnical exam. If you have to choose, the hydraulic structure should be the best. Nowadays, water conservation is also acceptable. It is not difficult to pass the test, but the structure is still the mainstream.