If you're talking about DX12's DXR, the option to disable it should be near the top of the advanced video settings menu, it's called "DXR Enabled".
If the option is either missing, is grayed out, or is already disabled, then I suppose the broken reflections you're seeing aren't from DXR but rather Screen Space Reflections (SSR), which in this game is known to be bugged on certain AMD GPUs (RX 6000 series, not sure about newer), and unfortunately the only way (as far as I know) to disable SSR is to set Post Process Quality to Medium or Low, sacrificing other visual effects as well.
There is a console command to individually disable Screen Space Reflections without lowering graphics settings, but from my testing the command is overwritten by the Post Process Quality setting every single time you spawn, even if you enter it as a launch parameter or use a configuration file. Should you wish to experiment with it, the command is "PostProcess.ScreenSpaceRaytraceEnable 0".
