You can try chainge.finance, in chainge.finance app, you can time frame your usdt and you can then use the TF-USDT to add liquidity against other stable coins with absolutely no impermanent loss.

The later is if you still want to earn more money from trading fees, but you don't want to, you are already rewarded for Time framing your usdt which also is zero impermanent loss.

The app is available for download in google playstore or iPhone Apple store  just search for Chainge finance.

You can see more here - https://www.chainge.finance/info/pool