I think you're mistaking k6 for another tool. k6 has only supported writing tests in JS. There are several other tools that are better suited for this single URL use case: ab, wrk, even Hurl. I doubt this will ever be supported in k6, since the focus is on scripting test logic, not firing off requests to a single URL (though this is certainly possible with a simple script).
I feel like I used to be able to run the CLI with just an URL and it would issue GET requests to it -- without needing a .js script to run
Am I crazy, did this never exist? Please bring back/add this feature