compare two array of values (nested or not) and return only changed indexes as array

FindUpdatedIndexes.php

<?php
    
    /**
     * It flattens multidimensional array to make arrays comparable
     * then compares request with DB (usually)
     * @param $request
     * @param $toCompare
     * @return array
     * @example request:    [["title" => "ABC"], ["title" => "DEF"]]
     *          toCompare:  [["title" => "ABC"], ["title" => "XYZ"]]
     *          return:     [1] (index 1 updated)
     */
    private function findUpdatedIndexes($request, $toCompare): array
    {
        $flattenRequest = Arr::dot($request);
        $flattenToCompare = Arr::dot($toCompare);

        $updatedEntries = array_diff_assoc($flattenRequest, $flattenToCompare);
        $updatedIndexes = [];
        foreach ($updatedEntries as $key => $value) {
            $index = explode(".", $key)[0];
            $updatedIndexes[] = $index;
        }

        return array_unique($updatedIndexes);
    }