I would add that the white cursor common in a lot of Linux distros is DMZ-White. It wasn't included in Zorin 16 when I installed it, but it's in the repository and is easy to install:
sudo apt install dmz-cursor-theme
There is a white and a black version in the package. I am using the white one. The cursor can be set to different sizes in Settings > Accessability.
As already mentioned, once installed, select it using the Tweaks tool.