Earlier quoted context omitted.
How is it easiest? Perhaps most accessible how society is currently setup, but beans, tofu, etc are all good for you, plenty of vegan body builders rely on them. This "high quality" protein myth is garbage.
Chicken breast and many other meats have a much higher ratio of protein compared to carbs and fat than tofu, beans, etc.
The amount of protein in seeds, tofu, seitan, nuts, legumes is plenty for almost anyone. And if you are power lifting even omnivore lifters take protein shakes after working out usually.