Some ideas

Don’t kill ust, buyback at market and burn some tokens.
Create pool 1:1 with other stablecoins for return only, not max supply at 1 time, but loaded from fees, future Luna sell. Max supply 100m usd at start or lower, and 10m every 1 week, it take years with slow buyback but it’s better than nothing, if Luna recover it happen faster.
After unlimited mint, they use death spiral to kill Luna, return network to before mint 1b or 10b, make penalty for exploit bad code for attack, destroy new supply. Luna is lost so revenge for it don’t make things worse I think.
New stablecoins different, some backed, but if ust v2 make some limit, and halt for mint if death spiral v2, recover only after stabilize situation. And limited mint to control stablecoin.
Ust failed, but it’s not backed now. Slowly exchange for other stablecoins is backed coin. If community want money back they use Luna, and in scenario when luna is back they slowly recover money.
100m at start, 10m is good too. If Luna recover you can add 1b usd even for return. If ust stay 5b mcap for 5b other coins or other capital for it(btc) its backed stablecoins too.
Other idea you must lost something. If crypto don’t die and Luna recover, you can return investment in ust, created by Luna, return by Luna.