I don't know the icon ,but check your apps that your using and restart your mobile.
This is "deactivated sensor" icon could be toggled on and off via developer settings
The main function of this feature is to turn off every sensor in your device,it also blocks the use of a Camera and the recorded voice from Microphone will be completely silent.
Thanks for your information.
Experience OnePlus Nord CE 5G in AR right now
by Susie Liu, 2021-06-10