Do you have a place for us to report bugs? Using an iMac on Catalina 10.15.4, scrolling the map with a middle mouse button sometimes causes the mouse pointer to disappear completely (unless it's over the dock icon bar) whenever the game window is the active window. Only workaround I've found is to quit and reload the game.
Hi! Sorry to hear that you're experiencing problems. There's an email address listed under the "Technical help" section here on the store page.
I'm not specifically supporting anything above 10.14 (I'm surprised to hear that it runs!), but if you can email me details, I'll take a look and see if I can't a fix!