unironically yes.
PSSR has been shown to have issues the moment the engine has to denoise anything.
and UE5 has to essentially denoise EVERYTHING.
by default basically everything shadow, hair, foliage and even cloud simulation related in UE5 is rendered as a dithered pattern, which the Antialiasing has to blend together (not actual denoising as such, but similar concept).
this makes any UE5 game susceptible to unwanted noise or flicker if the TAA method isn't perfectly tuned to correctly "blur" all the low quality shit that trash engine renders.
UE3 doesn't do that. everything is rendered without dithering. so PSSR basically has no real hurdles to overcome.
this is also why the devs let you chose post AA methods in this game, which basically no UE5 game allows, because if you did that with most UE5 games, the graphics would literally look broken, because everything is so low quality and dithered.
edit: if anyone wants to see how UE looks with no TAA, Alone in the Dark is one of the few UE games that lets you do it, by setting the AA settings to the lowest preset.
here is the main character's hair at 1440p... doesn't look too awful yet because the resolution is high enough... BUT,
let's imagine they want to port this to a lower end system, and had to run it at 720p... then it would look like this:
and that is why UE5 and later UE4 games look blurry as fuck the moment the resolution gets too low. because they HAVE TO BE blurry. without the engine literally blurring the transparencies, you'd see shit like that hair here all over the place.
hair quality in many UE5 games is essentially worse than hair quality of PS2 gen characters.
because this was low fidelity, sure, but at least it wasn't fucking dithered to shreds and blurred over to look coherent!