Trying to setup UTM parameters with form v2 and keep receiving "...type does not exist in FormValues"

I have spent so many hours just trying to figure out why Velo cannot recognize my form field key/field title to assign a utm parameter to the field… and no I am not misspelling the field key or getting it wrong.

import wixLocationFrontend from 'wix-location-frontend';

$w.onReady(function() {

    const query = wixLocationFrontend.query;
    let utmSource = decodeURIComponent(query.utm_source);

    // // Use direct element ID references to set values
    if (query.utm_source) {
        $w('#djform').setFieldValues({
        utmsource_1: 'test',
        });
    }
    // Debugging: Check that the values are set
    console.log("Source:", $w('#utm_source').value);
});

For some reason Velo can’t recognize utm_source1 when I’m trying to set that hidden field value to a specified utm parameter, right I’m just using ‘test’ as a dummy.