Every starting quarterback in the A.F.C. East was chosen in the top half of the first round within the last four N.F.L. drafts, infusing a bonanza of dynamic young talent into a division that could be — emphasis on — sneaky competitive this season.

For now, though, it is still very much ruled by the Buffalo Bills, who won the division last year behind a prolific offense and vaulted atop it Sunday behind a ferocious defense. The Bills, after throttling the Miami Dolphins by 35-0, will not know for some time whether this early switch in identity represents an anomaly or the nascent stages of a trend.

It was, for sure, an encouraging turnabout after a Week 1 defeat by the Steelers that mocked Buffalo’s off-season coronation as a tad premature. The comprehensive nature of Sunday’s mauling — three first-half takeaways, six sacks, four fourth-down stuffs — demonstrated the potential of a group that didn’t coalesce until much later last season.

But two games in for Buffalo (1-1), its offense — even with its five touchdowns Sunday — does not quite resemble the unit that last season passed for loads of yards and scored loads of points and, generally, rampaged up and down the field, smashing records and elevating quarterback Josh Allen into most valuable player contention.

The Bills created those championship expectations for this season by returning so many starters and adding receiver Emmanuel Sanders. So too did Allen, who spent the off-season honing his mechanics and building lower-body strength and seemed poised to continue his remarkable trajectory from inaccurate college passer to N.F.L. star.

But Allen had misfired on a few critical balls in last week’s loss to Pittsburgh, doomed in part by poor protection, and on Sunday he sprayed passes all over Hard Rock Stadium, completing just 17 of 33 passes for 179 yards. Dolphins cornerbacks Xavien Howard and Byron Jones — two of the best in the league — smothered Bills receivers. Throws that Allen connected on a year ago fluttered incomplete. Midway through the second quarter, Howard intercepted a pass thrown behind Bills receiver Stefon Diggs, and later an underthrown ball to Diggs should have been picked.

Bills Coach Sean McDermott said the offense lacked a rhythm in the first half, and Allen agreed.

“We’ve got some stuff to work on,” Allen said.

What stymied the Bills’ offense last week amounted to a flawless game plan by Pittsburgh, executed to perfection. Refraining from blitzing Allen, the Steelers generated pressure with a four-man rush and zone coverage. The reality is that few teams have the personnel to stifle Allen and the Bills in that way, and the Dolphins certainly are not one of them. Miami Coach Brian Flores favors man-to-man coverage and blitzes — lots of blitzes — and in the past Allen has made Miami (1-1) regret those choices.

Allen has won all five games against Miami since Flores took over the team after the 2018 season, and on Sunday he offset his scattershot passes by leading Buffalo on five touchdown drives. The Bills also went 4 for 4 in the red zone.

All Allen had to do to convert the first touchdown was to hand off to Devin Singletary, who raced 46 yards. But Allen finished with two scoring passes, to Diggs midway into the second quarter and to Dawson Knox on the opening possession of the second half. After that, it was 21-0 and the lead felt insurmountable.

After winning last week at New England, the Dolphins could have emerged Sunday as the most comfortable division leader in the league. Instead, they fell behind by 14 points midway through the first quarter, lost their quarterback, Tua Tagovailoa, to a rib injury, and committed three first-half turnovers, a trilogy of despair: one red-zone fumble, an interception in Buffalo territory and a muffed punt.

“Just had a blast,” said Bills safety Micah Hyde, who finished with 7 tackles and one sack.

The Bills sacked Tagovailoa twice within the game’s first three plays from scrimmage, and then his day got worse. On Miami’s second possession, Tagovailoa absorbed a blindside clean shot by A.J. Epenesa, who knocked him to the grass as his fourth-down pass meant for Jaylen Waddle sailed incomplete. Tagovailoa spent a few minutes on the ground before walking toward the sideline, clutching his ribs, and heading off to the locker room on a cart.

Much like a new homeowner who continues to scour real estate listings after closing, the Dolphins haven’t seemed quite certain about Tagovailoa, yanking him from games during their playoff chase last season and then earlier this month affirming publicly, and privately, that he was their starter despite multiple reports of Miami’s interest in acquiring Deshaun Watson.

And now the Dolphins will have to plow forward with Tagovailoa’s status unclear for next week’s game at Las Vegas. They do not see the Bills again until Week 8, and though it is possible that Patriots rookie quarterback Mac Jones spearheads New England’s rise into contention, it is most likely that Buffalo will be in first place then, as now, as last season, mounting its case as one of the best teams in the A.F.C.