The thing is, I've been through this many times before. The way I saw the Trek universe in, say, 1978 was very different from the way I saw it in 1998, which was different from how I saw it in 2008, which was different from how I saw it in 2018. Each new incarnation has reinterpreted the universe, transformed how it was portrayed and presented in some ways. The earlier stories were still presumed to have happened basically as shown, but a number of their specific details or assumptions had to be revised in light of the new portrayal. It's never been a fixed, immutable thing, not since they first brought it back to life in the movies, and it's disingenuous to pretend that it has been or that DSC is the first show ever to change it (which is a rehash of the exact same disingenuous argument that the purists trotted out against Enterprise).
But I never thought of those changes as making it "not Star Trek anymore." They forced me to reinterpret my own personal view of Trek continuity and history -- heck, the moment they said in "The Neutral Zone" that the year was 2364, I had to throw out and redraft my entire pencil-and-paper chronology -- but I didn't think there was anything wrong with that, because after all this was a work of fiction, a story that people made up as they went, and part of creativity is reinterpretation. If anything, I enjoyed the mental exercise of periodically having to rework my personal chronology when new episodes or movies forced me to rethink my assumptions or reassess which books and comics could fit in with canon. The changes let me continue to use my imagination, to keep my mind open to novelty and change, and that's healthy. A living thing is a growing, changing thing. Without openness to change, there is only stagnation.
Enterprise "tanked," but its additions to Trek continuity have still been acknowledged in subsequent productions. Reality is not a matter of opinion or like or dislike. The objective reality is whether the events and concepts of one television series are acknowledged in later television series and movies. That's the only thing that meaningfully, concretely defines what "counts" as Trek.