Then you hit the second requirement: complete bitmap theming, many times of a skeuomorphic kind. This is extremely difficult to do in something like Gtk/Qt.
1. Motif came first. Among people who knew what Motif is, the look of Windows 95 was widely recognized as being very similar to Motif to the point of being a knock-off.
2. See the diamond-shaped radio buttons in the second example. :)
Oh, I didn't see the second screenshot. Yeah that one is more like what I remember Motif looking like. The first one though is definitely going for the Windows 95 look.
https://doc.qt.io/qt-5/qtwidgets-widgets-styles-example.html