Quoting myself as I went and tested out whether this was actually a DLSS artefact. Different game, but it is about DLSS.
On my 4070ti, when I disabled DLSS, I still see little 'scratches' appear and disappear on certain surfaces (very flat low polygon metal doors or beams - you know, the Cyberpunk staple interior surface). Hardly noticeable but there. On straight lines as well. Rare, but visible. Enabling DLSS amplifies them a lot. At first I thought it might be my cheapy 4070ti (got the cheapest I could get). But the DLSS on quality mode makes it far more noticeable. Regardless, I can forgive the shimmer of DLSS on a few surfaces to play the game at a decent frame rate. I imagine AMD users feel the same as me. No biggie.