Three longevity brands come to mind: agnès b., ines de la fressange (for uniqlo or not), and claudie pierlot.
Lots of neutral tones but essentially dark navy, black, white and gray. Very Brit private school uniform-ish. Nothing flashy. Fit is closer to the body. Nothing to show off your curves, or your (family’s) wealth. Just perfectly-proportioned, impe…