Can i force apply Zorin’s unique window enlarge-reduce button to all apps?
I'm not exactly sure what You mean, but when it is the 2 buttons left beneath the close Button, You can activate them. First install gnome-tweaks:
sudo apt install gnome-tweaks
When it is installed, open it:
Do you have this problem only with special apps? Perhaps they don't use gtk themes but qt.
https://www.reddit.com/r/pop_os/comments/s5828g/minimizemaximizequit_buttons_not_showing_on/