Ant-Man is a somewhat ironic choice for a very, very big job: Kicking off the next phase of Marvel movies. “Ant-Man and the Wasp: Quantumania” works on one key level, establishing Kang the Conqueror as a truly formidable and worthy villain. Yet with its plunge into inner space, “Ant-Man” comes up short in almost every other way that matters.

Actually, the rapid descent into the Quantum Realm, a sprawling universe within our own, makes this feel as much like “Guardians of the Galaxy” as Ant-Man, with a vast assortment of strange characters and outlandish, otherworldly and too often murky production design.

With much of the action unfolding on that plane, the movie bears scant resemblance to the original “Ant-Man,” or even its sequel, which overcame its potentially mockable premise with plenty of comedy and a modestly scaled story.

Director Peyton Reed is back for the third time, and the movie begins with a similar sense of whimsy, but similarities to the franchise’s 2015 introduction pretty much end there.

“Quantumania,” by contrast, has a bad case of gigantism, as Paul Rudd’s Ant-Man/Scott Lang is drawn into the Quantum Realm along with the Wasp (Evangeline Lilly), her parents (Michelle Pfeiffer and Michael Douglas) and Scott’s now-grown daughter Cassie (Kathryn Newton, a nice addition to a family of heroes that keeps growing through shrinking).

What ensues is an especially psychedelic trip, with precious little grounding in anything that resembles recognizable reality. The most identifiable aspect involves this hidden universe chafing under the rule of a being so powerful that its occupants exhibit a Voldemort-like reluctance to even speak his name, that being Kang the Conqueror, played by Jonathan Majors.

Kathryn Newton as Cassandra

Although he made an appearance in Marvel’s “Loki” TV series, that didn’t prepare audiences for the Thanos-level threat that Kang represents, and Majors invests him with quiet menace and majesty – a sense of gravitas that’s no small feat given the contours of some of the dialogue. If Kang is destined to become the central antagonist as the next batch of movies again build toward an Avengers-sized showdown, Majors is the one thing to emerge from “Quantumania” on which anyone could hang their hat.

One structural problem, in fact, is that Kang’s power and the scope of his evil plans make the hero-villain pairing feel like a decided mismatch – to couch it in terms suited to Majors’ upcoming role in “Creed III,” asking a lightweight to go toe-to-toe with a heavyweight, one that got his start in the comics sparring with the Fantastic Four. It’s a point overtly made by Kang himself, who sneers at Ant-Man, “You’re out of your league.”

A global pandemic, obviously, significantly altered the theatrical playing field for everyone in Hollywood after Marvel’s smashing success with “Avengers: Endgame,” but the studio hasn’t felt like quite as much like a big-league player since that climactic event.

Thanks to its emphasis on Kang, the third “Ant-Man” has taken a necessary step toward something bigger, with the aforementioned “Guardians” and “The Marvels” sequels still to come this year. But it is, at best, a small step, and like much of Marvel’s recent output, only makes “Endgame” loom that much larger in the rearview mirror.

“Ant-Man and the Wasp: Quantumania” premieres February 17 in US theaters. It’s rated PG-13.