>It's important to note that many of the tricks (like hidden iframes from PSPs) that are used to make payments frictionless today are going to become useless as browsers roll out more changes to protect user's privacy (e.g. killing 3rd party cookies and storage).

Could you point me to resources to learn more about this? I work on integrations like this. Is it that iframed PSP integrations won't work at all, or they won't appear as seamless?