In my country all water bodies are public, and shores must be easily accessible, so no private beaches, lakes or rivers. Freshwater shores are publicly accessible up to 5 meters from the highest regular levels. If you have a river crossing your large estate, people can walk through by walking up the shore.
I’m a guy with a high “test IQ”, and my sister, who is in the normal range is way more succesful that me in most aspects of life. You don’t want high “test IQ”, you want “smart people” not the same, and far more difficult to measure. High IQ basically means you are good at solving certain types of puzzles