Laws intentions are to stall for enough time for the Shs. Him using shambles mobility, was the method used to extend the fight. That in of itself draining, on top of all the other shit oda showed. Its also literally described as a Vs type event.
The fights offpanled mostly, but Oda specifically showcased multiple encounters with them.
Oda also Implying he dealt with more off panel. In the 2 panels below u see the area cut up, an full of meteors. With fuji seemly being the one to have captured him.
all this isnt moot. Its the actual canon. Laws heavily fatigued as shown, an portrayed by Oda. No real way around that.
oda directly ties Law stamina to his df usage heading into the doffy fight. As shown above doffy/fuji efforts. Forces law to exert himself to the point, Doffy comment in surprise. On laws ability to still use it. With that implication an the strength difference, between law an Doffy/fuji. It has plenty of evidence.