Kristen Stewart was ready for her royal coronation.

After the world premiere of “Spencer” — her movie about Princess Diana — at the Venice Film Festival last September, Stewart, 31, was instantly heralded as the front-runner for the Best Actress Oscar.

“The Venice crowd hooted and cheered,” a promising report in Variety said of the world premiere, “showering Stewart with a three-minute standing ovation.”

The buzz was a well-deserved achievement from a real talent who critics adore, but nonetheless is often underestimated by the industry. Finally, it seemed the sun had set on her “Twilight” years, and Stewart would sail to the stage of the Dolby Theatre on a wave of goodwill.

It hasn’t turned out that way. In the six months since that euphoric premiere, Stewart has picked up no major awards outside of esoteric critics groups and is now a long shot for Best Actress.

She lost the Golden Globe Award (sure the ceremony was tarnished, but losing is losing) for best actress in a drama to Nicole Kidman as Lucille Ball in “Being the Ricardos.” Then Stewart didn’t even make it onto the rosters of the BAFTA or SAG Awards, the latter was won by current favorite Jessica Chastain as the title character in “The Eyes of Tammy Faye.”

When the Oscar nominations were announced in February, Stewart and her team probably heaved a sigh of relief that she had been included at all. She’s gone from top dog to underdog.

If Stewart emerges victorious Sunday night (8 p.m. on ABC), it will be a miracle thanks to the split affections of voters.

How did a performance of a lifetime nosedive at so many award shows? Emma Corrin recently won a Golden Globe for playing the same part on “The Crown” — an internationally beloved tragic figure.

One problem is that not many people actually like “Spencer.” The early raves were, for some, misleading. In-person film festivals were smaller last year, and often had more reviewers in the audience than producers, directors and actors. Much of the praise was coming from pretentious, snooty critics such as myself. (I unapologetically love “Spencer.” Now excuse me while I thumb through Proust.)

The film, directed by Pablo Larraín, is an eccentric fever dream that’s as much like “The Crown” as “Alice in Wonderland” is. It’s not a familiar biopic; it takes place over a single weekend, and characters don’t talk much — only stare. At one point, Princess Di’s pearls fall into her soup, and she starts chewing on them. Many viewers found that shtick too weird. And Stewart doesn’t even get to showboat like Meryl Streep did in the dismal “Iron Lady.”

The actress also appears uninterested in playing the Hollywood game that the leading contenders are old pros at. Chastain not only stars in “Tammy Faye,” but produced it and has been aggressively stumping for her movie since the Toronto International Film Festival in the fall. In fact, she was one of the only celebs to attend the fest in person — posing on glamorous red carpets while Toronto take-out joints were still making the rest of us use hand sanitizer to pick up our kung pao chicken.

In November, I watched Kidman speak to SAG Award voters after a New York screening of “Being the Ricardos,” and her charm dial was turned up to “ANNIHILATE.” During the Q&A, one voter yelled out, “You did it!,” like Kidman was a 3-year-old who figured out a tricycle rather than a very wealthy, experienced Oscar winner.

Stewart, meanwhile, does a few interviews — although you’ll find her on Howard Stern sometimes, unlike most red-carpet dwellers — and doesn’t gush or go overboard with self-back-patting. This is an admirable quality in a person, but not a campaigner.

Then there’s her résumé. There is a quartet of actors who are constantly running from their soap-operatic roles in the “Twilight” and “Fifty Shades of Grey” films: Stewart, Robert Pattinson, Dakota Johnson and Jamie Dornan. They’re all sensational, but the fangs, whips and chains follow them around like Lestat in New Orleans. Neither Johnson nor Dornan managed Oscar nods this year for their acclaimed turns in “The Lost Daughter” and “Belfast,” respectively, and Pattinson has yet to receive one. Stewart at least got nominated, but she just can’t shake Bella Swan.

Outside of the vampire-verse, she is also often the best part of bad movies, such as “Charlie’s Angels” or “Snow White and the Huntsman.” And her fabulous, boundary-pushing roles like “Clouds of Sils Maria,” a psychological drama in which she plays the assistant to Juliette Binoche, are ignored by Hollywood and overshadowed by the schlock.

You can be certain that Stewart will win an Oscar during what will be a long and fruitful career. But the events leading up to Sunday night’s ceremony all amount to Di-sappointment.