“ I can’t force a hinderence not to arise even if I’m some kind of right effort master, or presumably an arahat.”
This is opposed to the operation of right effort, whose four right endeavors begin with the effort to avoid:
"What now, o monks, is the effort to avoid? Perceiving a form, or a sound, or an odour, or a taste, or a bodily or mental impression, the monk neither adheres to the whole nor to its parts. And he strives to ward off that through which evil and unwholesome things might arise, such as greed and sorrow, if he remained with unguarded senses; and he watches over his senses, restrains his senses. This is called the effort to avoid.”—‘Buddhist Dictionary’, Nyanatiloka
If a hindrance does arise, it can be eradicated so that it doesn’t arise again, through starvation.
Restlessness is a higher fetter abandoned with the attainment of arahatship
Good observation. That is why I said worry is a serious hindrance. Restlessness is the last fetter to be abandoned before ignorance, so all the other fetters contain an element of restlessness, it is a primary formation in all unwholesome states. Restlessness is progressively abandoned as the fetters are eradicated, and the lower fetters bind to the sensual world, where they are in a gross form, so when abandoned there the bulk of the work is done. Not only that, but restlessness can cause other hindrances to arise. That is why the development of meditation on the breath, particularly in terms of the first two tetrads of the Anapanasati sutta is important.
if the five composites don’t belong to me
That is only in ultimate reality. In the present the practitioner is dealing with both conventional and ultimate reality, and the transition to ultimate reality actually involves severing the fetters.