I'm not sure how PayPal or Adyen for that matter deal with CB's internally as they both are merchant account providers and aggregate processors. I can tell you when we were with EMS Systems as our merchant account provider Wells Fargo was our processor. Wells Fargo did the dispute mitigation as they are independent of the buyer bank card, account provider and our bank. This is why when we'd a charge back it was instantly $75 gone no matter the charge amount, $1, wouldn't matter. That was $25 to EMS Systems, $25 to Wells Fargo and $25 fee from our bank (Chase) for the pleasure of reserving the $1 from our account. We used processing software called PC Charge, lease, $1400 annually thereabouts and come pre-configured, that is to say, locked to the providers like a Cellphone might be locked to TMobile.
After some years we switched to Card Service International who is both a merchant account provider and an aggregate processor. Those units at CSI completely independent of each other. CSI had a web interface albeit we bought processing software outright called IC Verify and used that. However when a dispute of charge occur we could respond via the Web Interface .vs. snail mail and that save us $25 or more. That is to say, with EMS/Wells back in the day they only allowed snail mail arbitration.
So say, you're circumstance and we were the seller. Initially as I said, it cost us $75 instantly. We respond to the chargeback written, that's another $25. You the consumer respond to our written defense lets say, we in writing respond to that, another $25 fee. Card Service's web interface allowed us to manage disputes without that continual $25 fee everytime we respond.
Now with PayPal when they came unto the scene Card Service warned us because PP was fronted by the Deutsche Bank as I recall, based in Germany. That means they governed under differing laws that Card Service albeit Visa/MC have rules, no matter where. Discover and American Express were not options at PP at least at startup as those entities did not agree to terms apparently. We processed all four and obviously have to apply to become a merchant accepting them, Amex is by far the most difficult. Amex as a consumer card entity is also the most protective of their customers by far. If you recall back in the day Amex used to advertise on TV shopping all over the world w/ max protection.
All that said and done one can only assume that Adyen or PayPal CB units are also independent of the rest of the operations as independent arbitration needs be there. It is what it is but the question comes to bare about "Is there a better way for eBay as a company and what might that look like?"
Clearly eBay is and has made strides in that direction towards certain types of high risk merchandise with authentication services. When you consider scope of all merchandise, well, thats insanity and it still really doesn't address many problems. eBay can authenticate a Coach purse but when the customer gets it and claims in smooshed and damaged in transit, welp... Problems. There really doesn't exist a 100% way to properly protect sellers and buyers, thats a big problem here at eBay IMHO.
I'm 150% sure eBay has considered numerous mechanisms whereby better safety for transacting partners has been discussed but no matter how one looks at it, each comes with its own set of aggregated problems. Likely why the company sticks with feedback, simplicity that covers broadband scope.
Now folks be they sellers or buyers who have poor experiences care say, "eBay doesn't care about sellers", "Buyer: eBay only cares about their sellers." Reality be neither statement is true or factual, eBay cares about both, they have to. Its the balancing act that is a truly formidable challenge and literally there is no company in online transacting that has done this better than eBay, not a one. Of course when one's victim be that buyer or seller it sure wont feel that way but that doesn't change the reality.
