Sailing downwind faster than the wind is possible. "Apparent wind sailing" https://en.m.wikipedia.org/wiki/High-performance_sailing

Even more astonishingly are the remote controlled sail planes than not only exceed the speed of the wind, their performance is limited by the sound barrier. "Dynamic soaring" https://newatlas.com/aircraft/dynamic-soaring-speed-record-s...

I think it's important to distinguish between downwind sailing and sailing before the wind, which is straight downwind, and cannot possibly go faster than the wind (you'd have a perpetuum mobile if you could do that).

From what I understand, faster-than-the-wind downwind sailing involves tacking between broad reaches, where the wind still comes in at an angle.