How can I make an app keyboard shortcut override the global default? For instance, Ctrl-Space is a commonly accepted "code completion" shortcut in several IDEs (IntelliJ IDEA etc.), however on the system level it is "change input source (language)" shortcut. I don't need other languages while in IDEA, so can I have Ctrl-Space trigger code completion in IDEA without changing the global default?

PS: I know about How can I set up a keyboard shortcut for switching input source? but the solution there is to change the global default (which I don't want to do).
I always used JetBrains products, and always using the 'ctrl space' for code completation. Never had such issue ....

In any case, just go to System preferences > Keyboard -> Shortcuts and disable that specific shortcut .

In my case, I have no such 'ctrl space' for anything listed ...