The existing Upsell element is a good start - but it is missing key capabilities when compared to One Click Upsell (OCU) on Shopify. Right now you can only choose one specific product to upsell regardless of what the customer purchases.

We need the ability to have (1) dynamic upsells, (2) Split testing, and (3) Analytics

(1) Dynamic upsells - the ability to make the upsell page or product that shows after checkout to change dynamically based on what the customer purchases;

(2) Split testing - the ability to do split testing so that we can, for example, choose two different upsell options to show up depending on what the customer buys. Then they would split the post-purchase traffic (i.e. 50/50).

(3) Analytics with conversation stats recorded, etc.

This is the Ecomm version of funnel page testing (just a bit more dynamic based on product purchased) and where OCU on Shopify is heading.

If this is an element / widget capability, it could be added in multiple places in the Post purchase flow (after checkout) including:

Upsell page > Downsell page (if they don't take the upsell) > ThankYou page

See OCU screenshots attached.

For reference, Here is version1 that GoHighLevel implemented which is a great start: https://ideas.gohighlevel.com/e-commerce-stores/p/one-click-upsell-for-e-commerce