Epic revealed that Unreal Engine 5’s Lumen GI does use ray tracing, but for indirect lighting only and that can be done without specialized hardware acceleration.
Epic also discussed how they used primitive shaders (a feature of the RDNA architecture also available on PC and Xbox Series X) on PlayStation 5 for its Nanite micropolygon geometry system.
Source: N4G PC Lumen GI Uses Software RT for Indirect Lighting Only; Nanite Exploits Primitive Shaders on PS5