Widgets looks like whatever you want them to look like, if the feel like they're from the 2010s its because the implementer made that choice, not because of a limitation in qtwidgets.
As I understand the philosophy of Qt, it does not (for the most part) use native widgets. They seek to draw widgets that match native widgets on a pixel-by-pixel basis. You can also change the look-and-feel (similar to Java Swing widgets) by using what Qt calls "styles". Ref: https://doc.qt.io/qt-6/style-reference.html
Ah, the magic times when screen resolutions were large enough to display lots of information, in proper 4:3 aspect ratio, just before they got flattened and the industry started treating them as short view distance TVs.
