I'd go with Cindy's identification.
From the Phlox divaricata subspecies without petals notched at the tip.
Does look a bit like Phlox pulchra; just got some potted Phlox pulchra in flower and was reading about confusions between that and Phlox ovata. Quite confusing! I needed to stick with Phlox paniculata (garden phlox) which, given good growing conditions, looks so spectacular growing in summer, here up North.
Flower beds under maples; only have experience with a flower bed under/adjacent to a couple of silver maples and does my experience fit with Cindy's description! I need to dig out a foot (depth) of rootlets in the bed (with adding compost and replanting) to keep the variety of perennials in the bed going (do some part of the bed every year).
Perhaps shrubs could hold their own against maple trees, better than herbaceous perennials; but I guess it's the maple that's got the start.