I have been using this monitor for the past 10 days.
Used it with both HDMI 8-bit and DP1.4 10-bit (8bit+FRC).
Use it with 150% scaling.
Display panel used: BOE MV315QUM-N20 (both UN650 and UN880, I've read, use the same panel)
(I've been having some luck with BOE panels, because even the laptop below I use it with has a BOE screen that I can use the whole day without eye strain.)
My laptop spec: Acer Helios 16 Neo - 13700HX, 4060, 2560x1600 16:10 165Hz version.
The display even at first glance, its backlight glow, feels very easy on the eyes (like my dell xps 13 2015 model which I could use for 10+ hrs a day without issue).
I keep the monitor on a 5in table riser, so the my eye level is in line with the middle of the screen.
The first day I had a headache after 3hours or so, but I continued using it for 9hrs that day.
Then on the second day, I used it for again 6+ hrs and this time the headache was much less.
From the 3rd day onwards, had no headache, and eye strain was almost absent or very very mild.
I now use it for 6+hrs everyday with little to no issues.
Brightness (average) I keep around 40 in the day and 20 in the night.
I sit around 2.5ft to 3ft away from the screen.
I have been buying and selling monitors because of headaches/eye-strain for the past 5 years, and this one is the best one so far by a long shot.
The monitors I previously tried:
-- LG 27UK650 IPS
-- Samsung SR350 IPS
-- LG 32GK650 VA
-- Asus VA24DQ/VA24EHE Eye care
(this was the easiest to use in this list, but still gave me a mild headache if I used it for more than a few hours)
So, I finally got my dream satisfied, of a 32" 4k monitor that I can use for an entire day without headache/eye-strain (just very little of it if I push the brightness too much, sit too close for long, or use it continuously for too many straight hrs).
The 32un650/un880 has a wide-color gamut, so colors look nearly as good as my phone's OLED screen.
It also has 5Wx2 speakers that sound quite good.
The only issue I have with the monitor is in the panel lottery part - I got some mild color uniformity issues, the left side is more yellowish and the right side is more reddish, but it is very mild and I see that only in a full white screen + focus on that).