For regular classes, A: 4.0, B: 3.0, C: 2.0, D: 1.0 (with some variance depending on + or - grades offered). For Honors/AP classes, every grade is essentially bumped up 1.0 point.
So yes, a 3.74 is around an A- average, but that's an A- average in less rigorous classes, without competition from top students. That's more of a B-/C+ average in AP/Honors classes (obviously the calculation is far from perfect, though, because every school has it's quirks- at mine, you couldn't get above a ~4.5 overall). For reference, I graduated high school with a 3.6 with multiple Cs and hardly any As, simply by virtue of taking the maximum number of AP/Honors classes. The point being, a 3.74 is not a terrible GPA, but good students are generally over a 4.0 these days.
So the student athletes averaged halfway between an A and an A-? So did I in HS, 15 years ago, and I was a pretty good student! GPAs are really hard to make sense of with all the AP bonuses and whatnot. Standardized test scores strike me as providing a more apples-to-apples comparison. Of course that’s increasingly difficult to do in a test-optional world. (My recollection from an article about ‘The Chosen’ in 2005 is that recruited athletes tend to score 100-200 points lower on the SAT, on average, at Ivy League schools. I would double-check had I not exceeded my monthly free New Yorker quota: https://www.newyorker.com/magazine/2005/10/10/getting-in/amp)