I'm on the verge of tears of happiness. The old-ass Huion tablet that works in #linux mint with pen sensitivity out of the box, didn't have drivers for the shortcut buttons. But after taking 2 seconds to install Input Remapper from the Software Manager (all GUI, no terminal stuff needed), it lets me bind any button to anything. Click record, press the button on the tablet, type in what I want it to do (e.g. ctrl+z). This is exactly what computers and software should be.