Is there still anyone competent that "doubt" so? As long as data transit through their infrastructure, in security, we must always assume that it's recorded (and later-on, eventually used), it has nothing to do with "settings".
I genuinely believe that people are insane to think otherwise, proof is that there has been millions(billions?) issued in fines for non-respect of this specific issue, why are people still having "hope"? It doesn't make sense, it's THERE, it's in THEIR DB.
The same goes for LLMs of course, every prompts is recorded and will be used, be sure of that.