UE5 by default uses a lot of flashy tech that is supposed to improve performance, but a lot of it only does so in scenarios that are already extremely unoptimized. Using more traditional methods tends to achieve the same fidelity at a fraction of the performance cost. But there's no time for optimization, and these fancy options "just work", so there ya go.

The end result is a poorly running blurry mess of a game, but at least it's out on schedule I guess.