A checkout page for each funnel

Your checkout page belonged to the merchant account, so every funnel selling through that account landed on the same page. A cold-traffic offer and a warm upsell funnel got the same layout, whatever each one needed.

The enemy is one checkout page standing in for every offer.

A funnel can now name its own checkout page, and the new Set Checkout Page node in page events picks one mid-flow, for example after a Product Check. When several apply, the most specific wins: the visitor's session, then the funnel, then the merchant, then the domain default. Upsells keep the merchant's checkout page, and it works the same on every gateway.

Try it: set a checkout page on one funnel, click a buy button in it, and confirm you land on that page instead of the merchant default.