FYI, the Singapore public debt is objectively not unsustainable. On the surface, Singapore's public debt-to-GDP ratio is at around 110%, which is slightly higher than the US. Over the course of Singapore's history, each term of the government operated on a balanced budget (i.e., revenue >= expenditure). The government bonds are issue to "develop the domestic debt market". In fact, the government is legally not allowed to spend the proceed of the public debt.
For more information, see https://www.gov.sg/factually/content/is-it-fiscally-sustaina....