Swapping $2.5M USDT into ETH via OTC

TradFi bro here, trying to accumulate some Ethereum using my USDT on the Tron network (TRC-20). I’d rather avoid big centralized exchanges like Binance because of a bad past experience, and I’m currently unable to swap directly on-chain.

I’m looking for ways to do this in a non-custodial manner.

Would appreciate hearing how others here have approached something similar.
Thanks in advance!