That site is not a reliable source for actual specs.... Further down they list 3000 nits peak which is correct...Hisense themselves rate the U8N at 3000 nits.
As usual, they go far above that. All sets are listed at peak brightness as far as nits go, the Bravia 9 included at 4000 nits...and the Bravia 9 costs 2000 dollars more.
For most users that are streaming nowadays, all streaming content is capped at 1000 nits....so, a lot of these specs are just smoke.
Displayspecifications doesn't even list the nits for the Bravia 9.
Specifications of Sony K-65XR90 GB. Display: 64.5 in, VA, Mini LED, 3840 x 2160 pixels, Viewing angles (H/V): 178 ° / 178 °, Brightness: 700 cd/m², Static contrast: 4000 : 1, Refresh rate: 40 Hz - 120 Hz, TV tuner: Analog (NTSC/PAL/SECAM), DVB-T, DVB-T2, DVB-C, DVB-S, DVB-S2, Cores: 4, Storage...
www.displayspecifications.com
The new TCL QM8 is 5000 nits for around 1500 dollars.
You had issues with a U6G, which is the el cheapo model...but if you look around, these things can happen with any make.
Audioholics doesn't get into video/tv sets much....just look on AVS and you will find brand new Sonys and Samsungs can have issues also....not to mention sets that develop issues after 3 or 4 years.
Nothing is made like it used to be made.