I think the take-home challenge might be working as designed: Filtering out candidates who are not yet experienced enough to handle the type of work the company

I think the take-home challenge might be working as designed: Filtering out candidates who are not yet experienced enough to handle the type of work the company does. What's strange here is that you're coming this conclusion without having actually ... seen a description of the take-home task itself. By all appearances, you are basically assuming the company was right (and knew what it was doing in designing this "test") from the get-go. My own observation indicates the opposite: not always, but far too frequently these companies either just don't describe the task properly; haven't checked if the components / targets actually still work with each other; or just plainly overestimate the time it takes to do the steps the first time, out of hubris (the way clients, managers, and developers tend to wildly underestimate the time it takes to do just about anything). Which allows them to chortle to themselves afterward: "See, all these candidates failed or ghosted us after agreeing to take the test. That must mean it's a good test. And also that we must be awesome, for having such a hard time finding candidates that meet our exacting standards. But with sea of bozos and wannabes out there, what are you gonna do?"