Superman more than pulls Surfer's weight through Thor, and Surfer can at least negate Superman's vulnerability to magic and amp him with cosmic awareness.
Even if Loki amps Thor in the same way, they can never take out an evolving Superman. Bar none.
Never mess with SS and S.
I always take All-Star into consideration. That MOS was cumulatively inexorable. I will always use what getting too close to the sun did to him as an example. Mitosis, deleterious cell build up, apoptosis, triple strength, unknown amount of new super powers, super imagination, super creativity, who knows what he's capable of in that state.