Another option is the modern authoritarian model, Competitive Authoritarianism [0] as deployed by Órban, Putin, etc.
You castrate the media, and take control of major vehicles to tilt the balance in your favour in quasi-sham elections; accumulate power in the executive while keeping the remaining seats of power under the thumb of the branch: legislative gets installed with sycophants/acolytes, judiciary power is tamed/dimished and regime-adjacent judges installed.
If you play this well you keep getting elected when elections happen and slowly twists more the sword into all democratic institutions.
Neither defaulting on the debt or starting a major war are effective ways to hold on to power, sheesh. He already tried to hold on to power, so you could just look at how he tried last time, that's one of the typical strategies. The other main one is a military coup.
Creating a global crisis is an excellent way to hold onto power.
Not that they started it or want it to continue, and not that I think Zelenski is anything other than a hero, but the case in point is Ukraine not holding elections since the war started.
When Zelenski told trump there have been no elections during the war trump, on camera, was delighted and said “very good”.
His options are start a major war, default on the debt, ?
Hold onto your hats