Hi there! This is Daria, Ecwid by Lightspeed. Sure, it is possible to move the Quantity field to the top right from the Ecwid Admin Panel. Please, open your Ecwid Admin -> go to Design -> scroll down to the Sidebar section and drag&drop the Product Quantity option, here is a video – https://ecwid.d.pr/v/Jq69DH
Once done, publish your WordPress site to apply the changes and check it. Let us know the results!