I've noticed this in a couple of games when playing at 4K over HDMI on an LG C2.
It usually manifests in the middle of the screen and usually in areas where there seems to be grass/sand. In Elden Ring it's evident when I'm moving and it looks like it reaches out from the top of my character. In other games you can just see it in a band across the middle of the screen usually.
I've had success in other games turning off any DLSS, obviously this isn't something supported in Elden Ring.
I can't see this banding/artefacting at 1440p.
Any ideas? I've tried to capture it on video here.