PayPal take the refund straight out of the sellers account if there is a dispute
eBay also takes the refund from the seller's account. They always did. Sellers are required to register a bank account with eBay from which eBay takes the cost of refunds.
eBay's new buyer protection fee adds nothing to the protection buyers already received. The only difference is that they now pay for it. All that's changed is that eBay recently stopped charging fees for private sellers, and instead started to charge fees for buying here - dressing it up as a "buyer protection fee".
Take a look at eBay's money back guarantee page - it still boasts that there is "no extra fee" for this, which there wasn't until now! Buyers are simply paying for protection that used to be free! https://pages.ebay.co.uk/ebay-money-back-guarantee/