Cabello clearly has an ear on her pop competition. “Bad Kind of Butterflies,” with a breathy vocal that tiptoes above furtive keyboards and deep bass abysses, is well aware of Billie Eilish. But there are no hard feelings; Eilish’s brother and producer, Finneas O’Connell, worked on two of Cabello’s new songs, “Used to This” and “First Man.” Through the album, Cabello moves between infatuation (“Living Proof,” “Dream of You”) and spiteful kiss-off (“Should’ve Said It,” “This Love”). But she concludes with true love in “First Man” — a song about convincing her father, “the first man who loved me,” that she has found a worthy guy. Ending at her wedding, it has the reassurance of a rom-com played just right.

Styles’s solo career has a more complicated agenda. In One Direction, along with the other four members, he grinned and clowned his way through songs promising affection, boyish charm and, eventually, the mischievous perks of pop stardom. Styles had the grainiest voice in the group, which often reserved it to arrive just when the verse pushed into the chorus.

But on his self-titled solo debut album, in 2017, Styles suddenly discovered both angst and rock history, apprenticing himself to music from decades before he was born. His voice turned modest, even self-effacing. His music suddenly reached back to the Beatles, David Bowie, the Rolling Stones and T. Rex, featuring hand-played instruments rather than electronic sounds, while Styles sang about addiction, a violent world, fierce jealousy and heartbroken despair. It seemed he couldn’t wait to brood. In the new, fairy-tale-like video for “Adore You,” Styles’s smile radiates destruction.

Image Styles takes a little break from angst on “Fine Line.”

“Fine Line” eases back on the angst, just a little, and focuses Styles’s attention on romance. He’s on his old home turf singing “Just let me adore you/that’s the only thing I’ll ever do” (in “Adore You”), while the hymnlike, bitterly self-accusatory “Falling” takes responsibility as an adult: “There’s no one to blame but the drink and my wandering hands.” It’s followed by “To Be So Lonely,” which nicely mocks the singer’s self-pity: “I’m just an arrogant son of a bitch who can’t admit when he’s sorry.”

Styles has also expanded his retro-rock timeline, while still working with the core brain trust from his first album, the songwriters and producers Thomas Hull and Tyler Johnson. His fascination with the late 1960s and early 1970s continues: “Canyon Moon” is a direct homage to the Southern California of Crosby, Stills and Nash, while “She” looks toward Pink Floyd with a somber, extended song about glum routine and yearning. “Sunflower, Vol. 6” is a glimmering, non-sequitur-filled, neo-psychedelic minisuite full of elaborate vocal harmonies and electric sitar.