I’m not the one asked, but to my knowledge there is no way to change that unfortunately.
It’s not part of the usual UI components (like the top menu bar).
I think there’s somewhere a bug or wishlist item to get rid of it already. I’ll link it if I find it.
EDIT: There you go:
And there’s also a question regarding it for the upcoming Q&A:
https://forums.flightsimulator.com/t/would-it-be-easy-enough-to-disable-the-spinning-white-circle-in-the-bottom-right-of-the-screen/443186