I would agree with b1exch.io, it's an actual no-kyc and they have their own liquidity as oppose to other instant exchanges who rely on 3rd parties for liquidity like from CEXes with kyc policies.
They are pretty new, however, they have deposited 0.2BTC to a trusted escrow here in bitcointal,k should any problem occur. You can tailor your trade size in respect to this amount, for instance you can split a bigger amount into a number of smaller trades.
I checked b1exch.io and yeah BTC to USDT is available.
I'm really curious how these no KYC exchanges like b1exch.io, like, is this fully decentralized, plus there's a Pool, for example, in USDT, there is a 2.4M USDT pool available.
So far, their announcement thread here in Bitcointalk is active, and people keep giving updates to the thread.
