If you don't want refunds, don't take a payment method where refunds are possible. Take crypto, take cash.
Anything involving credit cards, be it PayPal or not, will almost always side with the buyer if they dispute with their card directly. The payment processor (and/or credit card company as they're sometimes one in the same, like AMEX) has a few options. 1) They side with their customer, keep them happy, get the money from you and process the refund. 2) They go against their customer, piss them off, don't get the money from you and hopefully their customer doesn't just say "F U credit card" and quit paying it entirely. 3) Keep their customer, and you happy, pay their customer back out of pocket and let you keep the money. Which option you think they're going to go with 99% of the time?
The thing to remember is anyone paying with a credit card, they're not spending their money. It's the bank or card issuers money until they pay the balance without dispute. If there's a dispute, they're not in the business of losing money, so you're the one taking the hit. That's just how this works. You can gain SOME protections by using a high risk merchant account which will be stacked with fees and are most often used by the adult industry. Now there's more incentive for them to keep you happy as you're paying exorbitant fees for the privilege; effectively paying more in fees for "insurance" of better charge back protection.
What I would do is basically "self insure" as a middle ground. If you're paying PayPal 2% (I'm not sure of the exact rate these days) and a high risk merchant would charge 8%, put the extra 6% aside in a separate insurance account which you use to pay yourself back on any disputes. Remember, everyone is in the game to make money, if you're paying for insurance then the insurance company is making money from you. So unless you fall wildly outside the normal expected dispute levels you'll be best off with self insurance. I used this system for many years vs paying for shipping insurance on packages and I made out FAR better than paying USPS/UPS/FedEx for every package. I however don't recommend this for things like auto (and yes you can do that if you can prove to your state that there's enough money in an account) or home owners, as chances are a payout would exceed any amount you've saved; but shipping and chargeback protection, you're likely best off self insuring that.