setAttribute is not a function within Array

I'm trying to assign an attribute to every item in an array conditionally based on a radio value. I've gotten all the way up to actually setting the required attribute but for some reason, I can only set it on items individually, not to every element called in my array. I'm sure there's something I'm doing that's sticking out like a sore thumb but javascript is not my forté.

What I've tried: inside the forEach(function (item, i){item.setAttribute('required','true'}; - which returns "item.setAttribute is not a function"

    //assign required fields to variable
    const reqCollection = [document.getElementsByClassName("reqcheck")];
    console.log(reqCollection);


    document.addEventListener('DOMContentLoaded', () => {
        // on .conditional_radio-wrapper click
        document.querySelectorAll('.conditional_radio-wrapper').forEach(trigger => {
            trigger.addEventListener('click', function () {
                //assign variable for "Are you a realtor?"
                let realtorRadio = document.querySelector('input[name="realtorChoice"]:checked').value;
                //log realtorRadio
                console.log(realtorRadio);
                //assign variable for "Are you represented by a realtor?"
                let repRadio = document.querySelector('input[name="realtorRep"]:checked').value;
                console.log(repRadio);
                //assign required fields to variable

                //if they are a realtor or represented by one
                if (realtorRadio == "Yes" || repRadio == "Yes") {
                    reqCollection.forEach(function (item, i) {
                        //does work
                        item[0].setAttribute('required', 'true');
                        item[1].setAttribute('required', 'true');
                        item[2].setAttribute('required', 'true');
                        //doesn't work
                        item.setAttribute('required', 'true');
                    });
                }
                //else mark as not required
                else {
                    reqCollection.forEach(function (item, i) {
                        item[0].removeAttribute('required');
                        item[1].removeAttribute('required');
                        item[2].removeAttribute('required');
                    });
                }

            });
        });
    });

This line is problematic:

const reqCollection = [document.getElementsByClassName("reqcheck")];

You're getting an HTML collection array and encapsulating it in another array.

I would recommend just this:

const reqCollection = document.querySelectorAll(".reqcheck");

Then you can just iterate through

reqCollection.forEach(item => item.setAttribute('required', 'true'));