Or use a theme like WhiteSur which has built in support for both GTK3 and 4, plus the new mutter and libadwaita. I have it on my Debian 12 Bookworm install with Gnome 43.2 and it looks amazing.
FYI: Nautilus is GTK4 Before I applied the changes it was themed as default. Only took entering 2 extra characters to ./install.sh
./install.sh -l
There's no reason, I can think of, that Zorin OS 17 couldn't use it for their base.