my buddy showed me RE3 Remake on his 55" OLED in both 1440p and 4K. There was no discernable difference aside from a few crisper lines on shop signs in the distance
It depends on many things, for example the AA solution used.
On my OLED I can definitely see the difference between 1440p / 4k without any form of AA, motion-blur or other post processing.
Add such effects into the mix and the mileage varies a lot. With DLSS 2.0 some games actually look better upscaled from 1080p to 4k instead of a native 4k setting.
Other games look washed out even at native 4k because of the AA solution or low-res textures.
1440p is great too, but when it comes to finer details 4k can definitely make a visible difference. At these resolutions you're splitting hairs though (literally, as hairs and other such details often with transparency are usually where the difference is most noticeable)
I would say that most gamers probably won't notice that much of a difference when it comes to third party releases. Unless the dynamic resolution is unstable or goes below 1440p or the framerate tanks.