Snyder's movies failed, period. Making a profit doesn't mean they were successes, at least not in the way that WB wanted. People in general rejected his astetic and style of making "superhero" movies. He couldn't even break a billion with the first on screen meeting of Superman and Batman in live action. Aquaman, which rejected his style completely, kicked Batman v Superman's ass in the box office. Wonder Woman 1984, while having huge problems (mostly down to terrible casting), looks to be about as far from a Snyder film as its possible to get, and The Suicide Squad sure as fuck isn't going to resemble his films.
All of the successful DC films of recent years have rejected Snyder and his grim, Ayn rand obsessed bullshit. Sharing some actors with Snyder's films doesn't mean he succeeded at anything, it just means that WB liked some of the work of the various casting departments/people that worked in relation to him. His influence is already mostly gone (even The Batman is more of Nolan's kind of bullshit then Snyders), and Flashpoint will be the final nail in the Snyder DCEU coffin, even if some of the actors from a few Snyder lead films (possibly just Gadot and Momoa) will be sticking around for a few more movies.
Its grimdark, a bunch of people involved with the movie have talked about how dark it is, and it seems to be doing "What if Riddler was Jigsaw". The movie is grimdark shit. It might be a different kind of grimdark shit then Snyder's style, but it comes from the same idiotic mentality (started by Nolan's films) that Batman, and superheroes in general, need to be dark and brooding and have as little to do with the comics as possible. No cool gadgets or fun villains for Batman, Riddler just fucking murders people like he's in a Saw film and Batman has a bunch of handmade junk because god forbid any part of a live action Batman movie be fun or inventive.
So, The Batman is continuing a trend that Snyder tried, but it is probably more Christopher Nolan's fault.