I dont think we can really earn such huge returns as +swap and that too when our trade size is small. Further it is not risk free, we still have risk that price may go against our expectations.
If i am to trade safe i would simply buy gold at 1:5 leverage and be ready to put some more money if it fall 20%, There isnt any 100% profit strategy and if there is then its probably
some scams trying to rob you and rip you off your hard erned money and kill you off.