Run good candidates and you win. About all there is to it. Money didn't help Kamala, did it? She had a huge advantage in cash.
You seem to have a very base level of understanding of electoral politics. The POTUS gets more “free advertising” than any candidate in politics. And no candidate has had more “free advertising” than Donald Trump, probably ever.
Even most kindergarteners know who Donald Trump is. This isn’t some house race with obscure candidates. Again, money determines the vast majority of Congressional races. That’s not the same as a head to head presidential election, where both candidates are well funded and widely familiar. I would be curious to see what the historical numbers say on this, though. I’ll try to look it up when I get time. But you also have to recognize, the electoral college skews in favor of Republicans; so they can make up for less money in a general election, where money matters the least.