DS9 was also the first Star Trek to lean into a more serialised story telling thanks to the popularity of Babylon 5 at the time.
Apparently, this isn't entirely accurate. I recently stumbled upon a documentary behind-the-scenes thing on Prime Video... while the Star Trek producers were, as you suggested, accused of copying Babylon 5 with DS9, that isn't the real origin story of DS9's overarching plotlines. In fact, the studio initially rejected the overarching stories championed by the chief story writer, as they wanted something more episodic and easy to digest. It wasn't until those "upper management" types at the studio became distracted with Voyager that the producer relaxed and finally allowed the story writers to go all-in with their original plans; that's when they really pulled out all the stops for the Dominion war storyline. Turns out, DS9 was way ahead of its time, as it's arguably the most bingeworthy series of the entire franchise, today.
It was a truly fascinating documentary, by the way... it's called "The Center Seat: 55 Years of Star Trek" if you want to look it up. It forced me to toss aside a number of my previous misconceptions about the series. Chief among those misconceptions: In spite of the tremendous popularity of the franchise, the success of the movies, TNG and all of the subsequent shows was never a sure thing... behind the scenes, the franchise was almost always just on the cusp of being cancelled altogether for one reason or another!
I have greatly enjoyed almost all of The Trek -- but my favorite series in the franchise is absolutely the underdog: DS9.