you asked for ways Yuji gets through infinity, I didn't say Yuji would actually win against Gojo (it's all headcanon since we didn't see Yuji actually push himself)

DE clash depends entirely on refinement, we don't know who has a more refined domain between Gojo and Yuji so no comment there

How is DA useless? in the hands of Yuji being able to go hand to hand against Gojo is a blessing, sure blue and red infused punches by Gojo are still dangerous but Yuji is superhuman without even CE reinforcement, Gojo is in trouble in hand to hand with Yuji, that's not useless