The entire election cycle, inflation has been a key issue, but Harris/Trump don't have an easy edge over the other.
Trump can say "your administration has been in office 3 1/2 years. You're in office now. Inflation's growth rate may have come down some, but people are still paying something like 20% more cumulatively than they were four years ago" and he'd be right.
Harris can counter with "high inflation started under your administration, and the rate of increase has slowed under ours", and she'd be right.
Trump can counter with "significant inflation began under the last year of my Presidency because of COVID, which required an emergency response and was a worldwide public health crisis. Inflation hit due to the response, from supply chain disruptions to massive monetary expansion, but these were meant to be temporary. The current administration took trillions in new emergency spending and trade restrictions, and instead of pulling them back after the crisis was over, increased spending past that already high point and added new tariffs on top of mine."
Harris can counter with "you wanted even larger spending than what America had under your COVID response and greater tariffs than what we added after, yourself. Why should we be convinced that you wouldn't have added more spending and tariffs had you won re-election, much less brought us back to normal spending/tariff levels?"
And, of course, Trump has no such plan and no real response. In his primary last year, he ran adds against his opponents for daring to suggest budgetary cuts and fiscally conservative reforms. He's called for even greater tariffs than the ones that were added to his original ones. Harris has already agreed with this exact direction of his, even if there are some differences of degree.
They're left with a stalemate and cancelling each other out on what should be the greatest issue of the election. Would inflation be somewhat better under Trump the next four years than under Harris? Probably. Definitely if the Democrats had control of Congress. But it's not like he's got a clear case. There's an incredibly small window of difference between the two, and lively disagreement within it.
If the issue you're voting on is inflation, both have disqualified themselves from your consideration. The only real difference between the two on things Presidents can directly control unilaterally is on foreign policy (she's the Cheney candidate and he's the Tulsi one on that front). Among the other issues that they'd need the legislature for, the only major differences on policy are on things that couldn't get passed through Congress in the first place (they're not going to tax unrealized capital gains or something, thankfully).