ExpressJS and Promises with Promise all

I realize there have been posts about Promises and/or the Promise all function not working as expected because ExpressJS does not natively wait for all of the data to resolve, but I am baffled as to why my code is still not waiting on the Promises to resolve before sending the data back. The logs print the data I would like to send to the client. I've made the functions more generic for this post, but the function structures have not been altered.

app.get('/some-endpoint', (req, res, next) => {
    if(req) {
        try {

            return Promise.all([executeRequest(1, 2, 3), executeRequest(4, 5, 6), executeRequest(7, 8, 9), executeRequest(10, 11, 12)]).then(function(results) {
                console.log(results, 'Request results')
                res.status(200).send(results);
            }).catch(function(err) {
                return res.status(500).send(err);
            });
        } catch (e) {
            console.log(e);
            return res.status(500).json({status: 500, message: e.message});
        }
    } else {
        return res.status(400).json({status: 400, message: 'Bad Request'});
    }
});

That endpoint calls off to a function, executeRequest, which returns a Promise. The data from the response's "data" and "end" states are being resolved and logged through the console, but of course the response body is empty. I have refactored these function many times, trying to follow other answers and tutorials on Promises and Express, but I haven't been able to get the Promise all results to be returned in the response body. I am using the https module. Any help would be really appreciated.

function executeRequest(a, b, c) {
    return new Promise(function(resolve, reject) {
        var options = {
            host: host,
            path: '/some-other-endpoint-to-call-off-too',
            method: 'GET',
            port: '443',
            headers : {
                "Authorization" : a+b+c
            }
        };

        const callback = function(response) {
            var str = ''
            response.on('data', function (chunk) {
            str += chunk;
            console.log(str, 'data');
            });
        
            response.on('end', function () {
            console.log(str, 'on end');
            resolve(str);
            });
        }

        let req = https.request(options, callback);

        req.end();
    });
}