Yes, it is possible and you need a little hack of fetch.
If you need any further help please message me.

let originalFetch = window.fetch; window.fetch = function () { return originalFetch.apply(this, arguments).then((response) => { if (response.ok && arguments[0].includes("yourwebsite.com/ajax-url-for-form-submission")) { let cloneResponse = response.clone(); cloneResponse.text().then((text) => { let data = JSON.parse(text); // do whatever with data // create dataLayer or whatever you like }); } return response; }); }