I wouldn't stress about displaying anything pretty in a text window. Text user interfaces were obsolete 20 years ago and the only thing most people use them for now is running their shell and a text editor. 80x25 seems to be the default which most terminal windows start at. If someone made their terminal smaller, that's their problem. Just make it fit in 80x25 and don't sweat the little stuff right now. You're not that far away from being able to do graphics in SDL or a GUI in GTK or something. Not that you should run out and attempt that right away, you need to get a bunch more experience first, but it's a goal you should be able to see now.

As for ncurses, yes. On Linux at least, it'll be compiled as a dynamic library, which means whoever runs your program will also need to have ncurses. That can be as simple as something like sudo apt install libncurses, though. These types of dependencies are why most Linux software comes as packages even if they're just a single binary. Anyone compiling it will also need the header files and stub library, so they'll need to do something like sudo apt install libncurses-dev. So there are extra steps, but that's how things go. This might be a good time to learn how to link to libraries anyway. But pretty much any time you see a terminal program have color and dialog boxes and buttons, or programs like top or vim or less that are interactive and draw things arbitrarily on the screen instead of just with printf, they're almost always using ncurses. If you want to do terminal stuff like that, you can mess around with VT100 escape sequences of just use ncurses, which wraps all that up for you in a relatively easy interface.

But again, it's not a big deal. I wouldn't sweat it for now. Get checkers working with just printf and scanf and then either try to improve it, or move on. Dwelling on your programs, especially in the beginning, trying to make them perfect and iron out every detail is probably a waste of time. I'm sure you'll look back at the code for this project a month or two from now and cringe. You have so much room for improvement and dwelling on tiny details of your programs won't really help you improve.