But muh wacky survivor.
What it comes down to is that everyone knows how powerful Superman is. He's become the benchmark for all fictional match-ups. It's why people want their favorite self-inserts (Batman, Goku, whathaveyou) fight him, but in order to not feel like a jackass for punching a dude who is literally just hanging out in case you have a bad day and helping you, they make him evil so you can get a rush seeing him subverted. Couple that with DC running with Frank Miller's "Superman, stooge of the government" approach and Clark is being sold as some establishment thug in a cape who pushes a very specific status quo.
In most evil Superman stories that I've ever encountered, he's used more as a symbol than a character and is an obstacle for someone else to overcome. Red Son is one of the few inversions where he's the protagonist, and while he's more misguided than inherently evil, we actually see his struggles and why he feels the way he does without some petty excuse as a motivator.
If in the next decade we don't see an iconic Superman that actually lands with audiences, one where Lois isn't his morality chain which if shattered turns him evil, you'll basically have an entire generation that grew up with Superman being nothing but a tool to the general audience. When was the last time the dude really stood for something in mass media? That's what's really at risk. I'm not here to argue the merits of the Snyder films, but they did not land with the general audience nor really deliver the character that they knew through cultural osmosis.
That said, I don't think the Snyder Cut can really do a ton of lasting harm at this point because it's been so long since Man of Steel that Snyder's take has become more about him than it is about the characters. It's even called "The Snyder Cut," so it does shield the core characters from being read as their iconic selves, for good or ill. There's a big difference between saying "Superman" and "Donner's Superman" or "Miller's Superman," but it's the next big project that really matters. For that, I'm more concerned for Superman & Lois than the Snyder Cut, if only because if he exists to be a supporting cast spinoff to Kara, well you're going to effectively be telling your audience "Superman's done."