I tried Manjaro GNOME after a long while from Manjaro. But this really throwed me off. The desktop uses Matcha while gdm and the login screen uses Adwaita maia. Why? And I tried to set Matcha to the gdm theme but it is seriously broken.
If the theme is outdated why not use a up to date theme? There are plenty great themes that already have a green variant like Flat Remix, Canta etc.