One of the fantastic features of Oxygen is Conditions and the most powerful and versatile of them is the Dynamic Data condition.
This members-only tutorial shows how we can create a custom function that returns a count of the number of linked upsell products for a WooCommerce product and use this via the Dynamic Data condition to have an element be output only if there is at least 1 upsell (or conversely if there is no upsells if that is what you want) on single product pages.
Note: This is where/how we can specify upsells for products: