Never have,though I have had people request one a few times over the years.

I was never a Halo person growing up, never played one to completion. I think I might have played a demo of Halo CE, and then I tried Halo Infinite when it went free-to-play as a game to play with friends, but it never caught on.

As such, I've never had any particular attachment to Cortana or interest in her. And even if I did set out to make something with her, I wouldn't have any context within which to explore ideas. I don't know the first thing about her, honestly.