Filter the output of the the get_avatar_url function to use our local avatar

my_get_avatar_url.php

<?php 
/**
 * Filter the output of the the get_avatar_url function to use our local avatar
 * 
 * Guide: https://www.paidmembershipspro.com/custom-user-avatars-member-profile-edit-page/
 * 
 * You can add this recipe to your site by creating a custom plugin
 * or using the Code Snippets plugin available for free in the WordPress repository.
 * Read this companion article for step-by-step directions on either method.
 * https://www.paidmembershipspro.com/create-a-plugin-for-pmpro-customizations/
 */

function my_custom_get_avatar_url( $url, $id_or_email, $args ) {
	if ( is_numeric( $id_or_email ) ) {
		$user_id = $id_or_email;
	} elseif ( is_email( $id_or_email ) )  {
		$user = get_user_by( 'email', $id_or_email );
		$user_id = $user->ID;
	} elseif ( is_object( $id_or_email ) && ! empty( $id_or_email->ID ) ) {
		$user_id = $id_or_email->ID;
	}
	
	if ( empty( $user_id ) ) {
		return $url;
	}

	$avatar_id = get_user_meta( $user_id, 'wp_user_avatar', true );
	if ( ! empty( $avatar_id ) ) {
		$avatar = wp_get_attachment_image_src( $avatar_id );
		if ( $avatar ) {
			$url = $avatar[0];
		}
	}

	return $url;
}
add_filter( 'get_avatar_url', 'my_custom_get_avatar_url', 10, 3 );