There are a few sites that can help you swap BTC Lightning for LTC

1. Robotsats - http://robosats6tkf3eva7x2voqso3a5wcorsnw34jveyxfqi2fu7oyheasid.onion/
2. Sideshift - https://sideshift.ai (But they could ask for KYC at any time, though not always)
3. Coinswap - https://coinswap.click/
4. Boltz exchange - https://boltz.exchange/ (Only possible to exchange BTC LN and BTC)