My code is supposed to update "level" to the value of "level_num" but instead, it keeps returning 0.

function find_level() {
    let level_num = 0;
    document.querySelector("#easy").onclick = () => {
        document.querySelector("h3").innerHTML = `You chose Easy. Good Luck!`
        level_num =  1;
    }

    document.querySelector("#medium").onclick = () => {
        document.querySelector("h3").innerHTML = `You chose Medium. Good Luck!`
        level_num = 2;
    }

    document.querySelector("#hard").onclick = () => {
        document.querySelector("h3").innerHTML = `You chose Hard. Good Luck!`
        level_num =  3;
    }
    return level_num;
}

document.addEventListener('DOMContentLoaded', function() {

    let level = find_level();
    document.querySelector("h1").innerHTML = `You chose ${level}. Good Luck!`
})