C/C++ is only 'one language' (I know, but for sake of this discussion, may as well be), and even then, Intellij does just fine for me, even if it's not on par with Clion. To say it doesn't support mixed language development is silly. In one sizeable project I have python, js, TS, kotlin, Java, bash, groovy, even a little C. All of it works in Intellij ultimate with code completion, refactoring, goto definition, find usages, etc. And it does it does better and faster than the same project when attempting to use VSCode. VSCode starts getting real slow trying to find references and whatnot on significant size projects, and the refactoring is night and day better in Intellij.