The first link, the Asus PA279, should be an above-average choice for a photo editing display. No problem there. Its features are similar to the photo editing displays labeled “PA” by NEC and “SW” by BenQ.
The HP workstation seems like an old basic office workstation, not a graphics PC. The Xeon CPU has several major problems. It was first released around 2014, so it’s already a whole decade old. Also, for any multimedia work, many (all?) Xeon CPUs lack the Intel coprocessors that accelerate things such as video editing. For media work on Intel, the Intel Core series is preferred over Intel Xeon. Its NVIDIA Quadro M6000 graphics card was released around nine years ago and may be too weak for many current Lightroom Classic GPU-accelerated features. This computer seems like a terrible choice that is already very old and outdated.
The Dell workstation also has old components. The CPU was released 7 years ago, and one website says “This is a fairly old CPU that is no longer competitive with newer CPUs.” The Nvidia GTX 1060 6GB graphics card is about 8 years old.
All of this info I found using web searches. Those computers might run Photoshop OK for basic work, but the more you want to run the latest features such as AI Denoise in Lightroom Classic and generative AI in Photoshop, the more you want current hardware, like a 13th gen Intel CPU and NVidia GPU in the 30x0-40x0 model range. It isn’t always necessary to get hardware that recent, but the thing is, in the last few years there have been many advances in CPUs and GPUs that were not present in earlier generations, and many current graphics apps take advantage of those advances to make GPU acceleration and AI work much faster than the hardware from just 4 or 5 years ago.