[OED:] The primary sense was ‘away’, ‘away from’, a sense now obsolete, except in so far as it is retained under the spelling off (see off adv., prep., n.1, and adj.). All the existing uses of of are derivative; many so remote as to retain no trace of the original sense, and so weakened as to be in themselves the expression of relatively indefinable syntactic relationships. [...]
I already read OED's entire entry of 'Etymology' on OED. Where can I find more information, resources, or studies of of? How might of have been chosen for these derivative and so remote uses which retain no trace of the original sense? Surely not randomly?
See p 381, An Introduction to Language (10 ed, 2014) by Fromkin, Rodman, Hyams: 'As we have shown, linguistic changes do not happen suddenly. Speakers of English did not wake up one morning and decide to use the word beef for “ox meat," nor do all the children of one particular generation grow up to adopt a new word.
PS: I have tried to refine my question per this; please advise if it can still be ameliorated. I ask the above here because the OED asserts the influence of Latin's ab-, de-, ex- and French's de- on of.