Lumen IS raytracing. Like, literally. The reason lumen’s mirror reflections are blotchy is because of the real time global illumination. If you use lumen reflections with baked global illumination and hardware RT enabled, reflections are perfect.
Lumen already does ray traced refraction as of like 5.2 or 5.3. The only pitfall is that for it has to sample the lower quality translucency volume GI. Lumen GI and Reflections feedback thread - #1307 by BananableOffense