If I understand your question correctly, you removed the plastic cap and the nut that holds your wiper arm. Your wiper still feels firmly planted, correct? If so, I found it easy to simply fold up the wiper arm like when you wash your car. When I did this, the tension went away and my wipers easily pulled off. Pulling the cowl from here is simple. Pop the corner covers at the base of your windshield. Then release the two push pin fasteners on either side. Then carefully unlock the clips along the length of the cowl on the underside. You’ll see them when you get there. You can pretty much just pull the cowl off and away from the windshield but I’d work with a little more care to preserve the clips.