Googling your question popped up this article as the first result, it's been published just yesterday too Odd coincidence huh?

https://medium.com/@Bitpie/bitpie-wallet-enables-sending-usdt-onchain-transaction-without-btc-miner-fee-6a49d03572ce

Anyways.. I googled Bitpie, and while it's not really the most well-known wallet out there, I couldn't find a lot of people having issues with it, so it could be safe to use.

I'm not willing to test it out for myself, so to any guests reading this in the future if this title gets some traction, caveat emptor.