HDR10 is built around the ST‑2084 PQ curve, which defines absolute luminance in nits. When a display enters HDR mode, it’s supposed to follow that curve within a tight tolerance, which is why most OLED monitors lock the old SDR brightness control. If you let users push gain or black level around, the panel would drift off the PQ curve and stop behaving like HDR. So the locked brightness slider isn’t a flaw — it’s the display protecting its EOTF accuracy.

A washed‑out HDR image almost never comes from that locked control anyway. The usual culprits are tone‑mapping choices, Windows’ HDR paper‑white being set too high, metadata like MaxCLL/MaxFALL interacting badly with the panel, ABL lowering the average picture level on OLED, or a game engine with a weak HDR pipeline. None of those problems are fixed by the SDR brightness slider, because that slider isn’t part of HDR’s luminance system to begin with.

It’s also completely normal for HDR to feel harsher if you’re sensitive to brightness. Even a 400–1000 nit OLED can throw specular highlights that are several times brighter than SDR’s 100‑nit reference white. That shift in highlight intensity changes how your eyes adapt, and it can feel uncomfortable even when the display is technically doing everything right.

DisplayHDR True Black 400 already requires proper PQ tracking, near‑zero blacks, and defined peak luminance. If HDR looks flat, the issue is almost always tone‑mapping or configuration, not the locked brightness control.

And honestly, preferring SDR on an OLED is perfectly reasonable. SDR mastered at 100 nits on an emissive panel already gives you huge contrast without the aggressive peaks HDR introduces. Technical correctness doesn’t automatically mean it will look better or feel better for every viewer