You just can't draw the article's statements as even a reasonable conclusions without ignoring a whole host of things. They're largely comparing a general election to a midterm election, Rs show up for midterms more reliably than Ds, a drop is basically expected. Even compared to the previous midterm, that was with a very polarizing R in office, so we'd also expect a higher D turnout than one with a D in office. Plus add in consideration for the effects of voter suppression that's been building basically specifically targeted at the group in question.
This article is just bait created by someone who is either ignorantly or purposely misrepresenting the actual study's implications.
On the one hand, the article has a point as applied to very tight elections, especially considering that if you swing a couple tens of thousands of votes in a few swing states and we're knee deep into a second trump term. On the other, it's a fucking politico article and their writing is all geared towards creating a horse race and stoking fears and anxiety so that you keep reading politico, and so any nuance beyond "DEMOCRATS ARE IGNORING WARNING ALARMS AND THEY AREGOING TO LOSE THE NEXT ELECTION! ⚠️⚠️⚠️⚠️⚠️⚠️" is intentionally drowned.