Hello Sir, Can you provide me more details about it , like where you want to post purchase upsells? On the product page when a customer is browsing a product page? From where you want to do that click action? From admin end?
As per purchase upsell requirement I believe you also need the possibility to configure upsells for each product on product edit page - admin end. So how you like that interface be?
Once we talk, I will understand minor details of your requirement and will provide you a design layout of interfaces based on your requirement and also depicting my clear plans. Once you approve or modify it I will align my work accordingly.
My work will include proper support and 3 months free of cost bug fixing as per budget.
Thanka