SAN DIEGO — It could very well be that, for all of the hundreds of millions of dollars invested by the Mets’ National League East rivals this offseason, the billions committed by Steve Cohen to purchase the Mets themselves will carry the largest historical impact.

Until the Mets’ imperfect savior arrives, though? As Cosmo Kramer once advised, look away. They’re hideous.

The Nationals won the first full day of the winter meetings Monday with their seven-year, $245 million agreement to bring back World Series MVP Stephen Strasburg. Hence the defending champions joined in earnest the division spending party to which only the Mets, coming off a modest 86-76 record and third-place showing, have been a no-show.

“We’ve got to continue to be as aggressive as we can,” Mets general manager Brodie Van Wagenen said Monday at the meetings, “because teams aren’t getting worse around us.”

Score that as a rare understatement for the high-energy Van Wagenen. Strasburg joined beloved veteran and October hero Howie Kendrick as a returnee to the reigning champions, and more will come, be it Anthony Rendon’s return to third base or a high-quality replacement there.

The Braves, winners of the NL East for two straight years, have added a trio of external free agents — catcher Travis d’Arnaud, starting pitcher Cole Hamels and reliever Will Smith — while re-signing their own guys Tyler Flowers, Nick Markakis and Chris Martin, and they want to retain their hot-corner stud Josh Donaldson.

The Phillies, after hiring accomplished manager Joe Girardi, swiped Zack Wheeler from the Mets for the sizable commitment of $118 million over five years, and they’re clearly not close to finished, with infielders, starting pitchers and relievers still occupying their shopping list.

Shoot, even Derek Jeter’s lowly Marlins have sent a message of sorts by acquiring first baseman Jesus Aguilar and infielder Jonathan Villar, both of whom are eligible for seven-figure salaries via arbitration.

The Mets? Well, they hired Carlos Beltran to manage, and they re-signed reliever Brad Brach and traded for defensive outfielder Jake Marisnick. The two players serve meaningful roles for reasonable prices, and the rookie skipper Beltran possesses upside. Yet these transactions amount to tipping your doorman as your rivals buy buildings.

Van Wagenen, who refused to engage on any and all questions about Cohen’s negotiations to buy the team from the Wilpons and Katzes, contended that his group did its homework ahead of time. The July trade with Toronto for Marcus Stroman, the GM said, anticipated the high price of starting pitching on the open market. He continued: “The way our starting pitching was assembled, we had a little bit more of a solid foundation than some of the other teams did around the league. And we felt good about that.”

For sure, the Mets starting rotation’s front four of Jacob deGrom, Noah Syndergaard, Stroman and Steven Matz holds up well against most NL opponents. However, the departure of Wheeler, even if you agree with Van Wagenen’s stated contention that the Phillies overpaid for the right-hander, hurts doubly thanks to the Mets losing him and a division rival gaining him.

Van Wagenen played up his 2019 club’s second-half upturn, noting, “I think we think it’s closer to the true talent level.” Eh. What matters more, a club’s true talent level or its roster depth? I say the latter.

Only last week’s bombshell news — that the hedge-fund king Cohen, pending completion of talks (no slam dunk), would take over the franchise, albeit with Fred and Jeff Wilpon maintaining empty titles for a while — has prevented a Mets fans mutiny. Really, you get the sense that the faithful would giggle through a last-place finish in 2020 as long as it led to Cohen’s running things upon the schedule’s completion, just in time for Mookie Betts’ free agency.

“We are business as usual,” Van Wagenen said, in dodging a question concerning whether his contract features language protecting him against an ownership change, “and I’m excited for what opportunities we have in front of us.”

“Business as usual,” when paired with “The Mets,” lacks a positive connotation, to be polite. And right now, what should energize the tenuously positioned Van Wagenen the most is not the opportunities in front of the Mets, but rather the teams in front of them.