How to pass command-line arguments to IntelliJ itself, to alter behavior of IDE (not my own app with-CodePudding

I want to try using the new new Metal-based rendering pipeline on macOS for Java 17, as explained in

Can I point IntelliJ towards another JVM for its own operations, for a later version of 17 (understanding that I am operating IntelliJ in an untested and unsupported environment)?

Technically you can, but it might cause problems in your IDE I think? There's a warning in their documentation, see Change the boot Java runtime of the IDE to switch to a custom JDK.

How do I pass a command-line argument to that JVM when IntelliJ is launching?

Once your IDE is running, go to Help > Edit Custom VM options, see their Advanced configuration page.