JSFiddle - React, Tailwind, and code Playground

JavaScript

// Please open Console in your browser for look SpeedTest Result
    
    console.time('SpeedTest');
    let managerCount = 6;
    let bills = [199, 453, 220, 601];

    console.log(calculateReward(managerCount, bills));
    console.timeEnd('SpeedTest');

    function calculateReward(managerCount, bills) {
        const sum = bills.reduce((a, b) => a + b, 0);
        let award = Math.floor(sum / managerCount);

        while (award) {
            let compare = bills.map(amount => {
                return Math.floor(amount / award);
            })
            compare = compare.reduce((a, b) => a + b, 0);

            if (compare >= managerCount) {
                break;
            }

            award--;
        }

        return award;
    }