Mouse cursor disappears

Even if the problem doesn’t seem to be related directly to Rhino, I ask for your help because it is with Rhino that the problem is more “significant”.
After updating to Mojave, very often the mouse cursor disappears. For it to reappear I have to “improvise” combinations of keys or gestures (right click, ⌘ + ⇥ etc.) Any help is welcome.

iMac 27" late 2012 MacOS Mojave 10.14.6


I suspect you’re running an old graphics adapter; perhaps an Nvidia GeForce, that Apple is just not supporting very well any longer.
That sad news is your trusty 8 year old computer has outlasted it’s expected useful lifespan.