If you compare the styles of Settings and gt4-widget-factory, there are many changes on Settings that make it differ too much from any other modern GNOME applications using GTK4. Controls are bigger, inactive controls are more blurry, with a less visible border. All that is propagated to another system windows like the Open File dialog, that look as white as a piece of paper, with little contrast to say it some way.
Should not exist some consistency here?. Screenshots for comparison.