How have you turned ATC to purchases?

I sell digital files so there is no shipping. My ATC is 11%, reached checkout is 9%, but my conversion rate is just 3.8%. I only run meta ads at the moment and all events are set for purchase. I am not losing money at this rate but also not really making enough to make it worth the effort. I offer multiple products and buy one get one 50% off. I am trying to think of ways to either increase my AOV or convert some of these ATCs to purchases. Does anyone have experience converting digital files or any ideas what might be making people back out when there is no shipping? I currently do not have a funnel setup.