As explained in the dissent, they literally have to delegate the kind of authority in question here. It’s the hostile-genie problem: you can’t close all the loopholes in some iron-clad unambiguous way in finite space.
those loopholes and ambiguities should be left to the courts to decide with representation from both sides of the argument making their case and not some department head full of political bias and possibly an axe to grind favoring one side.
This assumes a US Supreme Court that doesn’t exist in 2024. If you want it changed, you would have to either wait till the judges change, or expand the courts.
No, their role is a lot larger than that and plenty of legal questions don’t hinge on this kind of thing. This is specifically about whether to tend to defer to agencies on the interpretation of definitions of terms and similar things related to their mandate, so long as they remain within the bounds of reason and plausibility.
A judge could go “nope, per Chevron this EPA interpretation of ‘pollutant’ looks reasonable in this context, that complaint is dismissed, but the rest of the suit may proceed”. Now they’re expected to let those arguments play out. But answering that particular kind of question definitely is not the whole point of the judiciary.