In the end we are now engaged in an impossiblity. Had the funds lent been expended creating viable assets and a strongly improved trade situation, then such debt might one day be addressed as debt. There is no sign of that. However you deal with it, the Germans end up owning assets unable to restore the debt and with citizens working overtime to tax them at every step.
In the end the Greeks truly must clean up their own house and do one other thing. that is cede banking authority down to the community level to allow an expansion of cooperative credit that then expands the economy and allows all the debt to be paid off.
The Greeks are part of not so much an empire as an association. However that does not allow a member to take advantage of that to foist failure onto the rest which is what was intended here by the Greeks. They are most fortunate that the senior members respect sound fiscal policies and live by them or the EU could never have existed.