QE would need to be taken away very gradually.
Even with QE Japan has experienced deflation
QE in Japan doesn't work because price level has gone to unrealistic level. Property and security price are governed by yield and return of investment, if they go up to unsustainable level, the cost will of course need to go down. Printing a lot of money will only make smart money leave the country to seek better yield and reasonable ROI business.
Japans a bit weird in that their debt is larger than their GDP by a significant amount but people trust that their money will not be lost or stolen in the system or the currency will collapse.
Benefits of having your own citizens holding the debt still to get ROI would be a significant challenge for them and they can't really print money to increase their debt so its a bit of a conundrum.
Debt larger than GDP is fine. A more meaningful measurement would be the country income vs debt level. So long as the country has good income via export and service, the debt can be expected to be paid back.