You want a commuter e-bike that lasts years, not months. Look for a sturdy frame with a rack integrated into the design so you aren't fighting with attachments later. Buying a bike that fits your life now means you won't need to upgrade in two years.
Bike shops clear out last year's models in late autumn to make room for new stock. You can get the same high-quality motor and battery for a fraction of the price if you don't mind a previous year's color or decal.
Remember that the 0% intro APR is a deadline, not free money. If you have a balance remaining after 15 months, the interest kicks in on the remaining amount, which will cost you significantly more.