A reputable buyer will only send you a paypal payment as a gift so chargebacks are pretty much impossible, otherwise don't do it.
Everything is possible, no matter what kind of payment type you've choosen. It's not so difficult to prevent user from filling a non-received claim with paypal, there are at least half dozen of different ways. Still none of those prevent user from filling an unauthirozed charge claim - 'I was hacked, somebody gifted $10k from my acccount'.
And what's most important, nothing could make you safe against CC/ACH chargebacks which are being originated in user bank, not the PayPal itself.