The Patriots defense was too slow to keep up with quarterback Josh Allen and the Buffalo Bills in a 47-17 loss in the AFC wild-card round on Saturday. Joshua Bessex/Associated Press

The Patriots spent an unprecedented amount of money trying to fix what was broken after last season.

Robert Kraft loosened the purse strings and Bill Belichick spent over $160 million in guaranteed money in free agency to add depth, patch gaping holes at certain positions, and put a more competitive team on the field in 2021.

To a degree, it helped.

Between free agency and the draft, where they landed quarterback Mac Jones, along with cornerstone pieces Christian Barmore and Rhamondre Stevenson, the Patriots were certainly more competitive, finishing at 10-8.

From the standpoint of finding a franchise quarterback and moving in the right direction, the Patriots’ season can be viewed as a success.

But the tape doesn’t lie.

They were woefully short on both sides of the ball when it came to competing with the AFC East’s new power, the Buffalo Bills, as well as other elite teams in the league.

After suffering an epic 47-17 beatdown to the Josh Allen-led Bills Saturday night in the Wild Card round, Belichick has to go back to the drawing board.

During his end-of-season video call with reporters, Belichick said he wanted to take a “longer view” while “evaluating everything we do.”

Ultimately, the goal now is to build a team capable of taking down the Bills, as well as other offensive-driven teams in the AFC.

With that in mind, what should the primary areas of focus be going forward? What’s missing from this team?

The answer remains plenty, but we’ll narrow it down to several categories below.

SPEED ON DEFENSE

The Patriots need to get younger, quicker and more athletic all across the board, but especially at linebacker. Their age and lack of speed was on full display against the Bills. None of the linebackers could catch Allen when he took off. They also couldn’t catch any of the receivers with swing passes coming out of the backfield.

Wideout Isaiah McKenzie once again burned them for significant gains.

Dont’a Hightower has had a career worthy of the Patriots Hall of Fame, but he often couldn’t keep up with the quarterbacks or backs, missing a number of tackles.

He’s due to be a free agent. So is Ja’Whaun Bentley, who’s younger, but also not fleet of foot. Veterans Kyle Van Noy and Jamie Collins also had their issues dealing with the speed of opposing offenses.

Clearly, the area needs to be addressed, considering they’re going to have to face Allen at least twice a year for a very long time. Slow and old is a recipe for more embarrassing losses in years to come against the high-powered offenses they’ll face next season and beyond.

Matthew Judon solved some of the speed issue up front, but he disappeared down the stretch. The suspicion is he was hampered by a rib injury suffered Week 13 against the Bills. Whatever the case, Belichick is going to have to make some tough decisions, particularly with Hightower and Bentley.

Rookie linebacker Cameron McGrone, their 2021 fifth-round draft pick out of Michigan, profiles as an upgrade speed-wise, if he’s able to make the team next year.

He basically had a red-shirt year, coming off a torn ACL in November.

The safeties are in better shape with Adrian Phillips and Kyle Dugger, while it remains to be seen what 34-year-old Devin McCourty, another free agent, decides with respect to his future.

The Patriots also have rookie sixth-round pick Joshuah Bledsoe, who should compete for a spot in the secondary.

But the point comes back to whittling away some of his tortoise-footed linebackers and replacing them with faster, speedier versions capable of handling mobile quarterbacks, along with their speedy weapons. The defense won’t improve otherwise.

The Patriots will likely use the franchise tag on cornerback J.C. Jackson, who played well this season, but he’ll need help for New England to go farther next season. John Bazemore/Associated Press

TOP CORNER

J.C. Jackson is an unrestricted free agent. The belief here is the Patriots will apply the franchise tag to keep him at least another year.

With or without him, the Patriots are missing viable depth in terms of boundary corners.

Jonathan Jones, lost for the year with a shoulder injury, will return and capably handle the slot corner position next season. He was sorely missed against the Bills and other teams with multiple weapons.

More than anything, the outside needs help.

Jalen Mills performed admirably playing out of position, but Belichick was still forced to play much more zone coverage to make up for teams taking advantage of man-to-man situations.

Whether it was Mills, Joejuan Williams, rookie reserve Shaun Wade, special-teamer Justin Bethel, DeVante Bausby, D’Angelo Ross or whoever was trotted out there, the better teams exploited the weakness.

Allen picked them apart no matter what coverage they were in.

Corner will be a priority in the draft.

WIDE RECEIVER UPGRADE

The Patriots don’t have a high-powered offense capable of erasing large deficits. Jones will continue to grow and improve next year, but it would help if Belichick added at least one difference-making receiver.

Allen’s game didn’t really take off until the Bills acquired Stefon Diggs. In an offense-driven league, it’s important to build around the quarterback.

The Patriots tried to upgrade last offseason by signing tight ends Hunter Henry and Jonnu Smith, as well as wideouts Kendrick Bourne and Nelson Agholor.

Of the lot, Henry proved a valuable asset to Jones in the red zone, while Bourne turned into their only big play threat. Against Buffalo, he caught seven passes for 77 yards, with two touchdowns.

Jones needs more.

Whether it’s bringing in a legitimate slot corner, or a game-changer like Diggs, the Patriots have to get up to speed with the current NFL. They have to be able to score points, and go toe-to-toe with the league’s offensive heavyweights.

Cutting ties with former first-round pick N’Keal Harry would be addition by subtraction.

As for other underachievers, it’s tougher to let Smith and Agholor walk given the hefty contracts both signed. The Pats would have to stomach significant cap hits if the Patriots dumped either one.

Smith was a virtual no-show in the passing game. The Patriots have to make better use of his talents. Ditto Agholor.

But since they pretty much have a collection of third receivers, the Patriots need to upgrade the talent in the arsenal, whether it’s in free agency, the draft, or via trade.