Wierd behaviour with my main screen - MacOS Sequoia

Hey guys, Currently using my MacStudio M2 Max on MacOS Sequoia. Since recently, I have this showing all the time. I never changed anything regarding monitor options and am using only one screen (which is a Panasonic TV). I find the blue thing always in the menu bar to be distracting and annoying, and I cannot turn it of : "Ne plus étendre" (French) does nothing when selected. Does anyone have a guess ? I'd really like to get rid of that, it's quite useless and stupid as I'm using one single screen with a MacStudio which does not have any monitor built in of course. Can't understand from what it is copied or extended. PS : Unplugging replugging the screen did nothing by the way, the computer has been turned on and off several times since I noticed it. Thanks in advance ! ;) https://preview.redd.it/zulmz74dp7ae1.png?width=962&format=png&auto=webp&s=57de9d2e69395621fd14245ad70d1164f99448b8