I don’t believe what we see from the genetically-engineered characters in DS9 is representative of the intellectual disabilities they possessed beforehand.
The implication is that, as Khan and the augments from the 20th Century developed a superiority complex and compulsion to enact their desires on the world, personality traits from Lauren, Patrick, and the others also became heightened. Lauren may have had learning disabilities and a high libido before her cognitive abilities were enhanced. The learning disability was removed, but her enhanced cognitive abilities tipped the high libido into a permanent state of nymphomania.
Likewise, Patrick may have had learning disabilities and emotional processing issues. The learning disabilities got “fixed” but the cognitive enhancements supercharged his emotional processing issues.
Also inferred from dialogue is Bashir’s enhancements were less intensive than the others, which prevented him from developing the kinds of neurosis the others suffered from. Jack, for instance, mentions a “full package” implying a full augmentation, à la Khan and his supermen.
I agree that there was likely censorship involved that toned down the presentation of the neurosis (a great deal of TV was like this at the time) along with a lack of nuanced understanding of the subject matter.
PAL the format has a higher resolution but DS9’s production process was for NTSC. They would not have redone the series in PAL so that version is likely scaled the lower resolution up to the PAL resolution along with the speed artifacts described.
I think the AI upscales we have now are a novelty but not a substitute for the DVD masters. Additionally, Marvin Rush used specific camera techniques to isolate characters from the background in the early seasons which in hindsight can the image looks undersaturated and muddy.
LCD technology is pretty poor at scaling up non-native resolutions, even in 2026. DVD is probably the best quality but your mileage may vary based on the screen you use. Streaming imposed an additional penalty due to additional artifacting from the low resolution and the usual penalty of increased blur and smudging during camera motion.
Counterintuitively, using an old CRT screen or a filter component like ShaderGlass or RetroArch will process the image in such a way that tightens up the blurriness the image and will let your eyes relax.
As much as I wish DS9 HD was a thing, it will almost certainly remain an artifact of contemporary production. There are ways to mitigate that reality, but no way to change it.