caustics and real refraction calculations are nowhere close to what gpu's can render realtime for now. even unreal, which i suppose is the most advanced realtime gpu renderer, can't calculate these realtime. so i imagine it will be a long while before you can see actual ior in gpu based (ie realtime) renderers.
quick edit. i think UE has maybe recently added, or is about to add realistic caustics / refraction.
AC26 ARM //
MBP M2 Max //
Ryzen 2700x | GTX 1660ti //
UE5.1 | Twinmotion | Corona | Rhino