Great condition, 0 dead pixel found, used with great care. warranty expired. After purchase, I can offer calibration for your qn90a by using Calibrite Display Pro HL(X-rite)(.icc computer file) for free. Compare to price.com display demo unit, this unit is way lower operating time.

Spec:
HDMI 2.1 & VRR, G-SYNC
50" 120Hz
3840 x 2160
VA panel, mini-led
10bits, 1000nits
DCI P3 100%


Rtings review: 8.4/10
Excellent native contrast ratio.
Great Mini LED full-array local dimming feature.
Removes 24p judder from any content.
Decent viewing angle.
Incredible HDR peak brightness

https://www.rtings.com/tv/reviews/samsung/qn90a-qled

In Rtings Accelerated Longevity Test, tested more than 18000 hours of testing didn't show degradation, meaning it's very durable for this model.