How The Oil Oligarchy Corrupted The World

mm, your chronology is quite off there.
the ottomans only existed from the late 13th century on (being a dynasty founded by osman) and were only a local power until the early 14th century.
the ‘holy roman empire’ which was neither the roman empire nor particularly holy, was a weird reincarnation of charlemagne’s dubious and illegitimate claim to the title of the roman emperor (the real roman empire continued to exist all through this time, it’s what we call byzantium these days, but it was legally and formally the roman empire, all the way down to its conquest, by the ottomans, in 1453). in reality the ‘holy roman empire’ was centered in much of what’s today germany, austria, czechia, and switzerland. other bits here and there as fortunes waxed and waned.

the khazars, on the other hand, were in their prime in the 8th and 9th centuries, and in the second half of the 10th century their power was pused back by the russians. a combined byzantine-russian expedition actually took back and destroyed the fortress sarkel which the byzantines had actually built two centuries earlier when the khazars were byzantine allies. shifting politics on the steppe, shifting alliances. byzantium played diplomacy in preference to war when they could. that was the real roman empire. the khazar power lingered for another century as a local chiefdom and a presence of people following jewish religion (and speaking the turkic dialect the khazars spoke) all through the western region of the old khazar empire – namely today’s ukraine – all the way down to modern times.
in any case in the 8th and 9th centuries there were no ottomans- the islamic power then was the caliphate in damascus and subsequently moved to baghdad – and the turkic steppe peoples, none of them had converted yet to islam. the seljuk turks who were the first to do do, did so in the first half of the 11th century (they captured baghdad in 1056 and won a history-changing battle against the roman empire (aka byzantium) in 1071).
the ‘holy roman empire’, which was called by pretty much everyone , germany, was nowhere on the map during almost the entire history of khazaria, only really coming into existence after otto in the middle of the 10th century just as khazar power was sinking into insignificance.
there’s a good book ‘the thirteenth tribe’ which describes much of khazar history, though the author tends to blow them up to sound more important than they wereally were. They were one more of the steppe kindgoms who played an important role on the fringes of the civilized world in the perennial superpower struggle between the greco-roman world (which in the middle ages meant byzantium) and the near east (persia and later the caliphate and later moslem turkic empires including the ottomans).
their real legacy is not the role they played during their ascendancy, but their fluke-of-history decision to convert to judaism, which left a large population of jews (who were nonetheless not ethnically jews at all) in eastern europe, which became a factor in historical events centuries later and a major factor in modern times.