Which payment system to choose for a trading platform like Etsy?

Question

PayPal

Good afternoon, we are making an online platform for small sellers of any small things, such as Molotok or Etsy.com. We want to do all trading on our resource through the payment system. The main disadvantage of the hammer, in our opinion, is that it is impossible to make a purchase on it without registration, as can be done on ebay or etsy.com. Both use Paypal.
What payment system with the possibility of a refund and a simple and understandable procedure for registering the Seller (for an individual and a legal entity) can you recommend. And, of course, with a tolerable commission, because. initially, we will return the entire commission of our sellers to attract users.
Thanks in advance.