Dylan Mulvaney Dreams of Privacy. Really.

Her bubbly video diaries about her gender transition were once a study in oversharing. Now on the other side of a nationwide boycott, she sees the value in keeping some things to herself.

It was early February, and Dylan Mulvaney was floating on the high seas — somewhere in the Caribbean, perhaps near St. Martin — on a cruise ship filled with nearly 5,000 gay men. Ms. Mulvaney, the 28-year-old performer, trans video diarist and cultural lightning rod at the center of an infamous Bud Light boycott in 2023, reported with a bright voice and wide smile that she was one of about “three women total” on the ship.

She was there to perform musical comedy for the cruisers; four cast members from the onboard production of “Mamma Mia!” served as her backup dancers. In a video interview from her cabin, Ms. Mulvaney identified the “one central question” that has lately been her North Star: “Does this decision help me become a Broadway diva?”

Ms. Mulvaney was playing a chipper missionary in the national tour of “Book of Mormon” in early 2020 when the coronavirus pandemic brought all theater to a halt. She redirected her boundless energy to making videos on TikTok, often adding melody to her intimate straight-to-the-camera addresses.

Her subject matter was varied at first: “Bridgerton” riffs, theater world fodder, a series interviewing animals at the San Diego Zoo. But in isolation, she began acknowledging some personal truths she had known since she was 4. In March of 2022, she recorded the first video in “100 Days of Girlhood,” a series of confessional TikTok check-ins about the beginning of her transition. The likes and comments rolled in. Ms. Mulvaney writes about the shock of jumping to a million followers in under a month. By 2023, she would have over 10 million.

Her online persona, as a friend describes it in Ms. Mulvaney’s forthcoming memoir, “Paper Doll: Notes From a Late Bloomer,” was a “very palatable” trans Ellen DeGeneres. “Ellen was one of my greatest role models — she made gay people seem not only normal but fun and relatable,” Ms. Mulvaney writes. But for her book, Ms. Mulvaney showed a bawdier side. (Hookups are recounted, sometimes in detail.) Some of her fans, she said, will probably find this book “a little raunchier than expected.”

At half past noon on the second day of the cruise, she hadn’t eaten yet, so she ordered Diet Coke and French fries. She wore white oval sunglasses as if they were a headband, a prim cardigan with gold buttons, pink Juicy sweatpants and, she said, a spritz of Baccarat Rouge. “This is the duality of my ’fits,” she said. “You’re either going to get Y2K Paris Hilton or you’re getting Audrey Hepburn.”