The Giants lost for five seasons with Odell Beckham Jr., and they can — and will — lose now without him.

But they wuz robbed.

And because the Giants are in full-blown rebuilding mode, they should now think long and hard about saying goodbye to Eli Manning.

Dave Gettleman must now draft Dwayne Haskins or trade for Josh Rosen and get a young franchise quarterback on the field sooner rather than later.

The return from the Browns — the 17th pick of the NFL draft, a third-rounder and safety Jabrill Peppers — wasn’t enough, of course. It never is for this kind of talent.

Nothing short of two No. 1s should have been acceptable for Gettleman and the Giants for a transcendent receiver in his prime.

Beckham apparently wasn’t all-in as a Giant, wasn’t happy in New York, grew tired of the losing, and Gettleman and Pat Shurmur decided they no longer wanted him to be a Giant.

One year after breaking the bank to keep him a Giant.

But still. Did they think he’d be that much of a distraction to give up on him?

“At this point I have no idea what to think,” Beckham told Kim Jones of NFL Network. “I’m trying to process it right now.”

He’s no doubt processing what it will be like playing with former LSU teammate Jarvis Landry.

“Bittersweet,” Beckham said. “It is what it is. It’s life.”

It is Saquon Barkley’s show now, and he’d better be prepared for an army of eight-man boxes.

And here we thought the end of the Jerry Reese-Ben McAdoo Era was rock bottom.

No. This is rock bottom.

First, Landon Collins walking out the door for nothing.

Now this.

A rebuilding team with a 38-year-old quarterback. Beautiful.

Remember Gettleman telling us you don’t give up on talent when he signed Beckham to his $90 million deal only a year ago?

Well, a year later, he gave up on arguably the biggest talent the Giants have had since Lawrence Taylor, even if Barkley appears headed to be included in that argument.

Ownership, which signed off on this, of course, must be tickled that for Beckham’s 12 games in 2018, $16 million in dead money has been left on the Giants’ 2019 cap while freeing up $5 million.

Beckham will enjoy catching passes from Baker Mayfield a lot more than he did catching them from Manning, that we know.

“I see the Browns trying to win a Super Bowl,” former Giants running back Rashad Jennings tweeted.

The Giants have no shot at the playoffs, much less a Super Bowl, with all the holes they have on their once-proud defense and Manning minus his most electrifying aerial weapon.

It is why Gettleman should have another no-holds-barred conversation with Manning, and the two should mutually decide that it would be in the best interest of both parties to part ways.

Gettleman could sure use the $17 million savings for his rebuild.

But he would probably be hung in effigy by all the Manning loyalists if he pulled the plug on him.

Manning, for 15 seasons The Pride of the Giants, deserves better than the worst kind of ending to a Hall of Fame career — Giants fans savaging him with boos during another depressing slog to nowhere.

How is the Kansas City model — rookie quarterback sitting behind a struggling Manning until he is deemed ready a la Patrick Mahomes sitting behind Alex Smith — supposed to work when the mob begins chanting early and often for the rookie?

And unfortunately for the next Giants franchise quarterback — whoever he is and whenever he arrives — he won’t get to throw to Beckham.

Shurmur labored long and hard to enlist Beckham as an ally, but it didn’t stick (see Lil Wayne interview … see Paris video … see hole in the Lambeau wall one week after That Boat Trip, see Stupid Pet Trick in the Linc end zone).

Gettleman had to be thinking: Beckham turns 27 in November. Unless he were to stay healthy and enjoy a historic season, it might not be as easy to trade him before the season in which he would turn 28 in November.

Beckham’s Dance Fever act was popular in the locker room. His work ethic was impeccable. Gettleman didn’t sign him to trade him, and reserved the right to change his mind.

Beckham made That Catch in prime time against the Cowboys and became an icon. He was a thrill and a joy to watch. He was made for New York.

Now he’s made for Cleveland.

Giants fans today: Oh, Hell.