@charbel-keedy
I don’t see a reason not to use .then(). But if you don’t want that for some reason, you can use async function instead:
setCalculation();
async function setCalculation(){
const z = await GetAllSumVotes();
let personPercentage = parseFloat((NewPersonVotes * 100) / z).toFixed(2);
console.log("roham",z, NewPersonVotes,personPercentage)
item.PercentageForPerson = personPercentage; //updated percentage
wixData.update("Competition", item);
}