Unfortunately there's nothing that Product Customizer can do about this, as the placement of elements of your product page and options is entirely up to your theme. Product Customizer must display options where your theme displays Shopify variants on the product page.
However, some themes do a have a setting to change the product page layout and where descriptions are shown! If you go to "Online Store" > "Themes" and click "Customize Theme" for your published theme, you may be able to adjust the layout under your Product page settings: