I am wondering if you have ever seriously considered issuance of Gisellian currency for countries facing unplayable debt (all of them, as far as I know).
The scheme I am imagining would have these govts paying off bonds due with G‑currency. Bondholders would then, ASAP, spend it on real items in the economy, where it would eventually end up as wages, where workers would spend it, ASAP, on taxes and consumer goods.
The demurrage, say 12%/year (= 12 x 1% stamps) would give this currency an annual velocity of at least 12 since any holder of the currency would want to spend it before each month-end tax stamp would be due.
Of course, any debt financed currency would have a velocity of less than 1, since that is the money definition of debt.