will is a deliberate or fixed desire or intention. schopenhauer thought that the inner will of each person was the key to his existence. he also thought that will could be seen in forces. eg gravity is the fixed intention for 2 bodies to move towards eachother.
schopenhauer thought the ultimate universe was just one universal will experienced by all things.
schopenhauer also said how people find it very hard to change their behaviour because of their will.
struggling implies unease or dissatisfication. maybe suffering is too strong a word. maybe dukkha would be the best word to use.
you also used the phrase "wilful choice" which means a deliberate or intentional choice. this isnt the same as "will" which is a fixed desire/intention. "will" implies there is no choice but rather that its an innate behaviour in which something will act in a fixed manner.
i remember you speaking of a natural order earlier saying how theres fixed laws such as when you jump off a building that gravity will act on you even if you dont want it to. but i dont think its a matter of fixed laws bu more a matter of greater will. gravity has a much more greater will than the will of a person so it will almost always win.
but at other levels the will of gravity isnt as strong or the wills act differently. i dont look at the world as a place with fixed laws but rather i look at it in terms of probability in which certain actions are far more probable than others. at different levels the probabilities change.
i think that if a law doesnt exist at other other levels then it shouldnt be thought of as a fixed law. same as rights or values. theyre not fixed laws but rather theyre more universally accepted or more probable at that level.
nietzsche thought that all things have a will and that this will causes things to want to express themselves in an assertive fashion and to expand.
and so this is causes dukkha because different wills will oppose eachother. and so there will be tension. overcoming this tension is the best happiness.
and yes nietzsche said people must begin an undergoing before an overgoing. he believed we had to forget all our fixed perceptions and notions of the universe so that we can create our own values. its kind of like a ressurection. dionysius drags man down to the primordial unity. a total state of chaos in which all boundaries and rules are dissolved. a state of nothingness. from there apollo the god of interpretating dreams and individuation picks up man as he creates values and laws.
also an ubermensch isnt a ruler. he creates his own values but he doesnt wish to rule people because to do that hed have to change his values in order than theyre agreeable with those people.
also nietzsche thought that god is dead.