Those display anomalies on his Intel Macs are so strange. Good to know it works fine on his Apple Silicon Mac though.
I also asked him if macOS supports the scaled 2304x1296 resolution on this 27" 5K monitor. I'm guessing no since Apple doesn't offer it on the Apple Studio Display either, which is a shame since Apple already offers it on numerous 27" 4K monitors.
What I really want though is a 5K 29.5" monitor, which I'd run at native "looks-like" 2560x1440, at ~200 ppi.
Are you saying you actually HAVE the Viewfinity S9? I don't see how you can form a valid opinion if you don't. Watching a video of it in no way shows the picture quality, so the only thing this video shows beyond the specs on the website is an unboxing.
Don't get me wrong, I wouldn't have high hopes for any monitor from Samsung when compared to the Apple displays, but saying it's "one of the worst displays" is a bit of a stretch at this point, particularly if you aren't actually using one.
Furthermore, it will probably need to be properly colour calibrated. Apple isn't perfect out of the box for colour calibration but on average is better than most other computer companies for colour calibration.
My 28.2" Huawei MateView (which is mentioned as an alternative in that video review) looked all washed out and had incorrect colours when first plugged into the Mac, despite Huawei's claim it is properly colour calibrated out of the box. So I ran a Spyder colour calibrator and now the colours look great. No light bleed either. Also, there are no sleep issues with this monitor on my M1 Mac mini even though a Thunderbolt 4 hub. Its main issue is there is a gradual light falloff towards the edges.