PS5 and Series X uses dynamic scaling to 4k. Dips fall to 1800p on PS5 and 2016p on Series X. Cube maps are generally in use for reflections and the game utilizes cartoony effects for exhaust, speed boosts etc.....
As for performance, the PS5 takes pole position here with only occasional 1 off dips here and there. Generally, Series X and S falls much more often during normal gameplay and suffers a bit more severely during busier races with lots of cars on screen and I can conclude more effects as well. Series X and S falls into the low 50's in these scenarios.
SideNote: As for Dynamic scaling numbers, I'm not the biggest believer of Oliver Mackenzie, I guess we can wait on Vgtech for more conclusive answers including tearing stats and a more in depth look at framerate differences. It's because Oliver likes to gloss over things a bit and tries to be a bit diplomatic about it. He also mentions that Checkerboard rendering is at play here, don't know why that would be used when there is FSR 2.1 available, especially since there have been no updates to the former since the PS4 PRO days. I will say the slight artifacting on zoom looks like typical CB but we shall see if other tech analyses agree,