Wanting some aspects of 90s series back is not necessarily based on nostalgia, it can (and is!) based on actually prefering the work done back then. Handwaving our arguments away by citing some outside sources that just have an issue with black, female or LGBTQ characters appearing or claiming it is nostalgia is just unfair strawmanning. I can again repeat the small selection of episodes I named earlier that are representativ of what made Star Trek so outstanding during that era and that dwarf anything that modern Trek has produced so far and that pffer a depth that totally eludes modern Trek: "Measure of a Man", "In the Pale Moonlight", "Who Watchs the Watchers" and "Hippocratic Oath", others have named other examples and if you need more I can quickly produce more (I am a German, so I will have to look episode titles up, because I have only been able to watch the series in English since I got them on DVD). Note that, for instance, TNG had an episode that dealt critically with social gender norms and arguably was dealing with trans issues in a sensible way at a time where in many countries gay sex was still partially illegal and same sex marriage was out of the question internationally, 1992's "The Outcast". People, who would have had all the reason in the world to hate TNG-ENT era Star Trek as well, because relative to their time, they were at least as progressive as current Star Trek, but not limiting it to surface level representation, but really integrating it well into the writing (I will note though that TNG was terrible with its female main cast members outside of Pulaski DS9 had excellently written female characters and VOY had a female lead). Has anyone here argued that this is the problem with either show? Absolutely no! So why, in response to criticism of the writing, and specifically highlighting via examples and description what it is that long-time fans on this forum are missing in Star Trek, are you talking about totally different people's problems.
Since you keep repeating this point: Do you not realise that this is adisingenuous deflection? Are there people who dislike Discovery or Picard for having gay, trans, non-binary, lesbian, black characters or female leads? Yes.