From pocnetwork:

"eBay signed into an agreement with Adyen back in 2018, to become the company’s official payment processor. Adyen will be the system on the backend. So the user will never leave eBay and may likely never even see the name (Adyen) during the process as it will all be branded as part of eBay’s checkout system.

PayPal is still going to be offered as a “secondary” payment option (along with options like Google Pay and Apple Pay), and will likely remain so until 2023 where eBay will then decide on completely dropping PayPal as an option or not (sounds like they will be as of now). Allowing users plenty of time to kick the habit and get adjusted to the new process.

This will bring the entire checkout experience into one place. No longer having to leave eBay, even for the briefest of moments. From adding to your cart to making your way to the order confirmation. From listing an item to sell to being paid and printing the shipping label. Everything can be handled on eBay’s platform.

eBay is giving users until May 28 (2021) to update their information so that their accounts are ready to go as things transition.

This will likely be a noticeable blow to PayPal as eBay has been in such a close relationship with the company since 2002. This has likely become one of its largest footprints in the timeline of things."

--Mike