How to change the link for all "go pro" buttons?

Hi, I am considering not using Pro Sites checkout page, because it's very difficult for me to customize. Instead, I think I will just use my own checkout page via my Stripe account.

My question: how do i change all the links that say "Go Pro" to my new checkout page - for example on plugins i''m requiring an upgrade for, and themes etc?

I don't want them going to the wrong checkout page.

Thank you