It is better now than later.

This is the mindset of the Giants’ coaching staff, an almost entirely new group assembling a unit with only a few starting spots and rotational roles up for grabs. Let the struggles happen now. Let the weaknesses and potential issues reveal themselves now.

Make the mistakes during practice and in the games that do not count. Unlike the banged-up and depleted offense, the Giants are mostly healthy on defense, and that availability allows for a more holistic opportunity to assess what players can and cannot do.

So, mess up on defense now so that the corrections are made before the real thing arrives.

“I’d rather have them have chances in the preseason to feel that stress and how they finish that play than the first time it happens is the regular season,’’ defensive backs coach Jerome Henderson told The Post.

There is so much focus on what the Giants are not doing on offense — Daniel Jones’ up-and-down training camp learning a new system, Kenny Golladay’s sluggishness, Kadarius Toney’s physical ailments — that at times, the state of the defense feels like a back-burner priority. Of course, it is not.

A spate of injuries at the center and guard positions has the Giants looking at a facsimile offensive line for Sunday night’s preseason game against the Bengals at MetLife Stadium. Head coach Brian Daboll admitted this could lead to a change in his initial plans to play Jones and the starters, as he did in the preseason-opening victory over the Patriots. Daboll could opt to have Jones, Saquon Barkley and others on offense sit this one out.

Bengals coach Zac Taylor said he does not anticipate using his starters in this game, so any work the Giants first-teams get will come against Bengals backups. No Joe Burrow and Ja’Marr Chase challenging the Giants’ secondary.

This is a vital time for several Giants defensive players, as many of them are holdovers from the previous coaching regime and are acclimating to new coordinator Wink Martindale’s far more aggressive scheme. The starting defense is set at safety with Xavier McKinney and Julian Love, and at one cornerback spot with Adoree’ Jackson. The slot corner job appears locked up for Darnay Holmes, who has been a turnover producer this summer. It is at the second starting perimeter cornerback spot where it gets dicey.

The salary cap-induced decision to jettison James Bradberry left a hole that Aaron Robinson is trying to fill. A third-round pick in 2021 — the Giants actually traded up five slots to get him — Robinson’s development as a rookie was stalled by a core muscle injury. The anticipation was for Robinson to start his NFL career inside as a nickel corner but this new coaching staff is using him on the outside. There have been good days and bad in practice and Robinson was not good at all in the first preseason game, giving up a touchdown, committing a penalty in the end zone and getting flagged for taunting after he broke up a pass play.

“First of all, he’s had a tremendous camp,’’ Martindale said. “You know, there were some 50/50 balls. The penalty, I mean you can’t have a penalty down there in the red zone. You can’t have a lack of communication, because that’s just kryptonite to your red-zone defense or your two-minute defense in any of those situations.

“Because if you go out there, especially out there when you’re out there on the island, you lose your technique and fundamentals, this league will find them. And that was a great experience for him in that situation being on the outside.’’

The starting defense will be without top lineman Leonard Williams, but the rest of the unit should be mostly intact. This is a group that at times has had its way with its counterparts on offense in training camp, and Martindale has not yet unleashed all the pass-rush pressure he surely is saving for the Titans in the Sept. 11 regular-season opener. Figuring out if Robinson can handle a starting job, and the identity of the third cornerback and third safety remain priorities.

At corner, rookie third-round draft pick Cor’Dale Flott’s progress has been slowed by injuries — the same with second-year Rodarius Williams — and rookies Darren Evans and Zyon Gilbert are in the mix. At safety, fourth-round pick Dane Belton’s progress has been slowed by injury, and veteran Andrew Adams and rookies Trent Thompson and Yusuf Corker are in the mix.

“A lot of young unproven guys,’’ Love said. “That doesn’t mean that we have any lack of talent, I think we’re a talented group.’’