How to find overlap object?

Hi @@AG, here is an example script to show you one approach. - Mark

/**
 * @fileOverview Example usage of `itemsIntersectingItem` function.
 * Select an item, then script will change selection to any items intersecting.
 * Note: uses geometricBounds to determine intersections.
 * @author m1b
 * @discussion https://community.adobe.com/t5/indesign-discussions/how-to-find-overlap-object/m-p/13793143
 */
function main() {

    var doc = app.activeDocument,
        item = doc.selection[0],
        page = getItemPage(item);

    if (
        item == undefined
        || page == undefined
    ) {
        alert('Please select an item on a page and try again.');
        return;
    }

    var intersectingItems = itemsIntersectingItem(item, page.allPageItems);

    doc.selection = intersectingItems;

};
app.doScript(main, ScriptLanguage.JAVASCRIPT, undefined, UndoModes.ENTIRE_SCRIPT, 'Select intersecting items');


/**
 * Returns an item's page or spread, if any.
 * @param {PageItem} item - an Indesign or Illustrator PageItem.
 * @returns {Page}
 */
function getItemPage(item) {

    if (item == undefined)
        return;

    var page = item.parent;

    while (
        page.parent != undefined
        && page.constructor.name != ('Page')
        && page.constructor.name != ('Spread')
        && page.constructor.name != ('Document')
    )
        page = page.parent;

    if (
        page.constructor.name == 'Page'
        || page.constructor.name == 'Spread'
    )
        return page;

};


/**
 * Returns items whose bounds intersect
 * with the item's bounds.
 * @author m1b
 * @version 2022-10-04
 * @param {PageItem} item - an Indesign PageItem.
 * @param {Array<PageItem>|PageItems} items - an array or collection of Indesign PageItems.
 * @returns {Array<PageItem>}
 */
function itemsIntersectingItem(item, items) {

    var intersectingItems = [];

    for (var i = 0; i < items.length; i++) {

        if (
            item !== items[i]
            && boundsDoIntersect(items[i].geometricBounds, item.geometricBounds)
        )
            intersectingItems.push(items[i]);

    }

    return intersectingItems;

};


/**
 * Returns true if the two bounds intersect.
 * @author m1b
 * @version 2022-10-04
 * @param {Array} bounds1 - bounds array [t, l, b, r].
 * @param {Array} bounds2 - bounds array [t, l, b, r].
 * @returns {Boolean}
 */
function boundsDoIntersect(bounds1, bounds2) {

    // TLBR
    return !(
        bounds2[0] > bounds1[2]
        || bounds2[1] > bounds1[3]
        || bounds2[2] < bounds1[0]
        || bounds2[3] < bounds1[1]
    );

};