SpeedFan (or potentially other hardware-related) software stops working when BattlEye is enabled
BattlEye is blocking certain software (like Speedfan) that is using kernel drivers which contain known security issues that can be exploited by cheats.
Epic Games does not support such software and therefore cannot provide a fix.
Please make sure that you are using the latest version of such software or, if there is no newer version available, contact the developer/vendor of the software to notify them of the problem.