What's the best alternative?
It's easy to say "don't use PayPal" but if you're going to say it, you need to do the hard part of suggesting a viable alternative for eCommerce that has as broad a reach and acceptance as PayPal. Stripe? Almost none of the outlets I do business with use it. Venmo? Same company as PayPal. Back to using credit card numbers? The more we spread those around online, the higher the chance they get stolen and used, probably in refund scams like the one OP describes.
People need an alternative with some degree of trust and most consumers, by my reckoning anyway, would prefer a single entity that is accepted everywhere. Right now, that's unfortunately PayPal.
What's wrong with Trustly, Adyen and others among the ~40 alternatives we maintained integrations with at the casino operator I was working at almost ten years ago?
Personally I've had way less issues with stripe, especially in terms of fraud detection.
Also not sure what and where business is but in Europe it's common to just use a proxy provider where credit card is just one of many options and you use a central gateway (similar to stripe)
You'd have to check your local options. At least one of my local banks offers something more advanced than PayPal. And there are several of these proxy providers in my country.
Edit:// if you just want low fee, fast and risk free transactions we all know there is only crypto