You could try using https://www.tradeqwik.com/. I just made a test deposit and it worked fine (looks like they only read the chain every 5 minutes though).
Unfortunately, there's not a heck of a lot of buy side liquidity right now, so you might not get a great price.
(Disclosure: I own TQS which means I get a small fraction of trading fees. Small as in ~0.003% of fees...)