1) Have some collateral (BTC, ETH, USDC, something you somewhat trust);

2) Use collateral to borrow 1M USDT from AAVE/Compound/whatever;

3) Trade 1M USDT for ~1M of some USD-stablecoin you trust (USDC?);

4) Wait for USDT to crash;

5) Buy 1M cheap USDT from decentralized exchanges (using the USDC you kept aside), which will cost you less than 1M USD;

6) Pay back loan (keeping the difference as profit) and get back your collateral.