That’s because Cinnamon is actually a fork of an ancient Gnome release
mate is what originally spawned from gnome 2. while cinnamon was built from gnome 3, it has been completely separated from it for a decade.
both are under active development, run current applications, and offer what would be described as a more 'traditional' desktop environment (compared to gnome shell or ubuntu's unity). they're both lighter-weight then gnome, with mate being a bit leaner than cinnamon.
mint would be my suggestion for op, and any of the default mint desktops, including their other option--xfce, would be suitable for op's use case.