Redirect member away from the Member Profile page if they do not have access to view this member's profile.

my_template_redirect_member_profile_permissions.php

<?php
/*
 * Redirect member away from the Member Profile page if they do not have access to view this member's profile.
 *
 */
function my_template_redirect_member_profile_permissions() {
	global $pmpro_pages;

	if ( empty( $pmpro_pages ) || empty( $pmpro_pages['profile'] ) || ! is_page( $pmpro_pages['profile'] ) ){
		return;
	}

	if ( ! function_exists( 'pmpro_hasMembershipLevel' ) ) {
		return;
	}

	$pu = sanitize_text_field( $_REQUEST[ 'pu' ] );

	if ( is_user_logged_in() ) {
		// Get the current user's ID.
		$user_id = get_current_user_id();

		// Get the profile user.
		$profile_user = get_user_by( 'slug', $_REQUEST['pu'] );

		// Build a comma-separated list of  the profile user's levels.
		$profile_user_level = pmpro_getMembershipLevelForUser( $profile_user->ID );

		// Build the logic of whether to redirect away.
		$redirect_away = false;
		if ( pmpro_hasMembershipLevel( 1, $user_id ) && $profile_user_level->ID != 1 ) {
			// Can only see other Level 1 users;
			$redirect_away = true;
		}
		if ( pmpro_hasMembershipLevel( 2, $user_id ) && ! in_array( $profile_user_level->ID, array( 1, 2 ) ) ) {
			// Can only see Level 1 or 2 users;
			$redirect_away = true;
		}
		if ( pmpro_hasMembershipLevel( 3, $user_id ) && ! in_array( $profile_user_level->ID, array( 1, 2, 3 ) ) ) {
			// Can only see Level 1 or 2 users;
			$redirect_away = true;
		}
	}

	if ( ! empty( $redirect_away ) ) {
		// Redirect back to the directory page if available. Otherwise, redirect to home.
		if ( ! empty( $pmpro_pages['directory'] ) ) {
			wp_redirect( get_permalink( $pmpro_pages['directory'] ) );
		} else {
			wp_redirect( home_url() );
		}
		exit;
	}
	return;
}
add_action( 'template_redirect', 'my_template_redirect_member_profile_permissions' );