Kazunori Yamauchi has been speaking to various media outlets to discuss what is next for the Gran Turismo. He has not discussed a new game though it is
www.thesixthaxis.com
It is likely to have a 120fps mode, either with or without ray tracing. But maybe the reason they used lower resolution ray traced reflections was to get higher framerate.
GT7 is said to use lower resolution checkerboarded ray traced reflections. The 3090 can't do 4k raytracing, but if the raytraced reflections were lower resolution ray traced it'd likely have no problem.