From https://helpx.adobe.com/lightroom-cc/using/whats-new/2023-3.html#denoise
Only works on proper RAW files, which have a Bayer or X-trans pattern. So no linear DNGs, TIFFs or m/sRAW.Reducing noise from your images just got easier with AI-powered Denoise. You can now enhance photos taken with high ISO settings by eliminating noise efficiently. With this addition to the Detail panel in Lightroom, you can now reduce noise automatically and manually.