Ever since he left the Bronx boy band Aventura a decade ago to go solo, the bachata luminary Romeo Santos has been teaching a graduate seminar in melodrama. He is a disciplined thespian, especially across his “Fórmula” series, a collection of albums driven by audacious, genre-crossing collaborations and intrepid experiments with pop, hip-hop and reggaeton.

Santos, 41, has an unwavering devotion to bachata — a Dominican genre with Black and working-class origins known for its bedrock of amargue, a peerless brand of bleeding-heart bitterness. Still, he has never really been a traditionalist. (His 2019 album, “Utopía,” was a rare exception, an LP that genuflected to and recruited genre-defining forebears like Raulín Rodriguez and Anthony Santos.)

Instead, he has consistently sought out new ways of refreshing bachata’s templates while developing some of his own trademarks — signature catchphrases, caustic disses and salacious onstage antics. He has brought in English lyrics and hints of R&B, and ventured into the world of reggaeton, most memorably alongside Don Omar (“Ella y Yo” from 2005) and Daddy Yankee and Nicky Jam (“Bella y Sensual” from 2017). Years before the music industry became obsessed with Anglo pop artists singing in Spanish, he had A-list figures from the world of hip-hop and R&B appearing on his albums, including Usher, Nicki Minaj and Drake. At a moment when other high-profile stars are experimenting with bachata (see Rosalía and the Weeknd on “La Fama,” as well as the intro to Bad Bunny’s “Tití Me Preguntó), it feels even more urgent to recognize that Santos saw its potential for global popularity and creative reimagining all along.

On “Fórmula Vol. 3,” the latest, 21-track installation of the series and his fifth solo album overall, Santos includes unexpected team-ups with Justin Timberlake and the regional Mexican star Christian Nodal. He also doubles down on the theatrics, submerging listeners further into his acerbic torch songs about betrayal, bitter revenge and unrequited love, sometimes with mixed success.

Of the collaborations, “El Pañuelo” with the Spanish star Rosalía is an immediate standout: Her melismatic vocal runs flutter into focus in the intro, and in the chorus, a call-and-response lament between the two singers recalls the 2002 hit “ Te Quiero Igual Que Ayer” by Monchy y Alexandra. The misty-eyed merengue “15,550 Noches,” which unites the genre stalwarts Toño Rosario, Rubby Pérez and Fernandito Villalona, ​​is nostalgic, doleful and explosive all at once. And on the booming Christian Nodal feature “Me Extraño,” a song about returning to yourself after being wronged by a paramour, Santos finds a perfect balance between the thematic commonalities of mariachi and bachata.

His dramatic flourishes are most palpable when he makes full use of cohesive metaphors and potent storytelling as on “Ciudadana,” a diaspora tale about a romance separated by borders, complete with aerial sound effects, like a flight attendant announcing a landing. Santos’ yearning, crisp falsetto is most effective in these contexts: On the corrosive opener “Bebo,” an alcohol-soaked send-off to a duplicitous lover, his voice trembles with despair, and he feigns intoxication in a spoken outro. It’s a vocal performance that magnifies the best parts of bachata’s theatrical core.

But Santos missteps when he falls into religious and gendered tropes. On “Nirvana,” a ballad written as a monologue to God, he attempts to reconcile the existence of social and political injustice with God’s assumed benevolence. It descends into low-level political signaling, with an exculpatory name-drop of the Dominican dembow star Tokischa and the Puerto Rican rapper Anuel AA, who have been blamed for promoting crime and drug use.

Both “La Última Vez” and “Suegra” reproduce antediluvian gender stereotypes. “Suegra” is the bigger disappointment, though it is expertly produced and arranged by Iván “MateTraxx” Chévere, Martires De León and Santos. The nylon-string guitar-picking complements his high-pitched tenor as Santos sings about the clichéd image of an overbearing mother-in-law. But then his lyrics turn violent, as he describes poisoning her coffee and pushing her body off the side of a cliff in a car (the song even ends with a car crashing sound effect). In a country that currently has the second highest rate of femicide in Latin America, the gag doesn’t land as a lighthearted farce; it just feels irresponsible and out of touch.

“Sin Fin,” a collaboration with Timberlake, is perhaps the most paradigmatic song on an album rooted in both the past and future. Its syrupy celebration of endless love sometimes forgets on sappy idolatry, but it also maximizes Timberlake and Santos’s talent for pop sentimentality. The track is a full-circle moment for Santos: On Aventura’s second album, the band transformed ‘N Sync’s “Gone” into a bilingual bachata requiem. Here he once again finds common ground between two worlds once thought irreconcilable, demonstrating how bachata can stretch beyond both its real and imagined borders.

Romeo Santos“Formula Vol. 3”