Will Ferrell is building up a head of steam. Seated in the nondescript hotel conference room that’s been seized for our interview, the actor has taken up the subject of transphobia in Hollywood films like “Ace Ventura” and is running with it.

“The entertainment culture has taught us to have a flippant attitude that trans people aren’t real people,” Ferrell says. “It’s silly. It’s make-believe. Obviously, we’re getting closer to educating everyone —”

“Are we?” his friend, former “Saturday Night Live” colleague and now road-movie co-star Harper Steele interrupts, stopping him hilariously short. Her deadpan is laced with the ring of truth.

This is the animating question of their documentary, “Will & Harper,” which follows the pair on a cross-country road trip as they unpack Steele’s 2022 coming out as a trans woman. Along the way, Ferrell and Steele meet Indiana Gov. Eric Holcomb, a supporter of anti-trans legislation; connect with the trans community in Peoria, Illinois; suffer hateful trolling in Texas; and experience the unexpectedly warm embrace of dive-bar patrons in Oklahoma. Within the structure of an absurdist buddy comedy from the goofballs who brought you “SNL” sketches like “Oops! I Crapped My Pants” and “More Cowbell,” the Netflix film, now streaming, offers one of American pop culture’s most successful portraits to date of the contemporary trans experience — unafraid to answer “all the questions you’re not supposed to ask trans people.”

You might even call “Will & Harper” the trans “Will & Grace.”

“The impact that a sitcom like ‘Will & Grace’ had for the queer community, gay community, is massive,” says the film’s director, Josh Greenbaum. “It’s certainly not what we would call high art, but it speaks a little bit to something we were striving for with our film. I love the expression that laughter is the shortest distance between two people. I’m a big believer in it. We talked about making sure that our film was funny and accessible and an easy on-ramp.”

As with NBC’s landmark sitcom, though — praised by then-Vice President Joe Biden for doing “more to educate the American public than almost anything anybody’s ever done” but panned by some LGBTQ+ observers for oversimplifying queer identity for straight viewers — this spoonful-of-sugar approach cuts both ways. For Steele, who admits that she loves an “aggressive approach” when it comes to discussing trans rights, “ ‘normalizing’ is a reductive word that puts queer people in a place. It makes me feel like the goal is gay marriage, not generalized liberation.”

The ability of “Will & Harper” to walk a fine line between being edifying and didactic, entertaining and superficial, is woven into its very structure, with its stars’ connection deepening by degrees until they reach the Mojave Desert town of Trona, where Steele, in a shattering moment, reveals the depths of her past self-hatred. At every juncture, it threatens to leave important stones unturned, vital context unaddressed — and at every juncture, instead, it confronts the viewer’s skepticism head-on.

Not that they planned it that way. Jettisoning an early idea to build the film around comedy bits, Ferrell, Steele and Greenbaum found themselves subject to the vagaries of nonfiction storytelling, and thereby stumbled into the journey’s most bracing scenes. They did not expect, for instance, that a gag involving Ferrell trying to eat a 72-ounce steak in under an hour at a Texas steakhouse would expose him and Steele to uncomfortable leering from the other patrons and a subsequent flurry of social media abuse. Nor did they know that Holcomb would be at a Pacers game they attended in Indianapolis, where the governor and Ferrell were introduced courtside — leading to an on-camera reckoning for the actor about the rudiments of effective allyship.

“If we were in a moment like that again, I wouldn’t hesitate to (ask), ‘By the way, what are your views?’ ” Ferrell says. “Just because I’m OK with poking the bear a little bit more. Especially if I had some knowledge going in. Literally last night at dinner, the waiter misgendered (Steele). He said ‘Hello, gentlemen.’ And I said ‘Nope.’ ... That’s now how I react because it feels natural.”

But politicians’ and pundits’ use of transgender people as a scapegoat would not be possible without their historical mistreatment, or outright erasure, in popular culture. As for the roughly 60% of Americans who do not know a trans person, according to Pew, “Will & Harper” hopes to be an introduction: “Now you know Harper,” Greenbaum says.

Such positive messages will compete for attention against transphobic rhetoric from such high-profile figures as Dave Chappelle and Ricky Gervais, even on the same platform. But Steele refuses to take their comments seriously — or bend her own creative process simply to combat them.

“When egos get hurt, people troll,” she says. “And I’m looking at a lot of these people and they’re enjoying the trolling.

“I want our voice and my example to be louder, in the end. I just hope it drowns out the voice that is weaker, and that’s my method. I don’t like confronting.”

“Will & Harper” actively seeks to neutralize the cries of “cancel culture” by taking no topic of conversation off the table. With Ferrell as her curious everyman interlocutor, Steele explains her choice of a new name, discusses her physical appearance and sexuality, acknowledges her bouts of suicidal ideation; she introduces her children, visits her sister, and shares her letters, diaries and most painful memories.

As a result of this vulnerability, she offers a remarkable invitation to viewers who might otherwise pass judgment, or avoid the conversation entirely, out of fear that they will say the wrong thing, or cause offense, or discover that their experience is not in fact universal.

“One of the many things that I loved about her transition is her constant wanting to talk about it,” says Steele’s friend and former “SNL” collaborator Kristen Wiig, who co-wrote and performed an original song for the film. “(It fostered) this open dialogue to keep those connections, make them stronger and to really explain what she had been going through for years that a lot of us weren’t privy to.”

The film has already succeeded in sparking that dialogue among viewers, according to Greenbaum. At one Sundance screening, he recalls meeting a woman and her son, a trans man, who had been estranged since his transition but reconnected when she bought them tickets to “Will & Harper” as a sort of cinematic olive branch. Steele, for her part, admits to having more nerves over “Will & Harper” resonating with trans audiences than persuading cis ones — perhaps because she understands firsthand the harm produced by Hollywood’s powerful mirror.