I've just noticed that Ebay is changing from PayPal to Ayden. This was announced in 2018, resurfaced in February 2020, and I believe it is beginning to be rolled out.
Ebay has the usual "it will be a better experience" statements, without spelling out all the actual differences. Searching ebay's help page for ayden adyen returns several pages, none of which mention ayden adyen, doh!
I've done a quick search for ebay and ayden adyen. There are mutterings about being paid directly to your bank account, having to provide extra detailed financial information, problems with matching ebay names and bank account names, not understanding how this will work for occasional private sellers, etc. But I haven't found anything I regard as solid information.
So, if someone can point me to a high quality statement, I'd be grateful.