How to remove blue dot indicator for Screen Mirrioring?

Since I updated to Sequoia (running 15.2 atm) there is a blue/ purple dot in the top right corner which I think is an indicator for screen mirroring. If I move the mouse to the top right corner I can see that screen mirroring is shining in the same color and the dot disappear. The dot stays in the top right corner no matter what program or app I'm running. It even shows up when the screen saver is running.

The thing is that my Mac Mini M2 is only connected to my LG OLED and no other display.

If I hit the Screen mirroring button the top text is reading "Duplicate or Extend to: LG TV".

Why?!

There are no other screen connected to the Mini so there shouldn't even be an alternative to extend the desktop. It's like Sequoia thinks that my Mac mini is an Macbook laptop which would have a build in screen. On a laptop I would understand the Duplicate or Extended desktop alternatives, but not on a computer which doesn't even have a screen.

Does anyone knows how to turn this function of?

I don't want Sequoia to possibly burn in this dot on my OLED screen and ruining it.

[Re-Titled by Moderator]