Populate ACF Select field with menu names - Use the acf/load_value filter to load values to a Select field. https://www.damiencarbery.com/2022/12/populate-acf-select-field-with-menu-names/

acf-load-select-values.php

<?php
/*
Plugin Name: Populate ACF Select field with menu names
Plugin URI: https://www.damiencarbery.com/2022/12/populate-acf-select-field-with-menu-names/
Description: Use the acf/load_value filter to load values to a Select field.
Author: Damien Carbery
Version: 0.1
*/


add_filter( 'acf/load_field/type=select', 'dcwd_load_select_values' );
function dcwd_load_select_values( $field ) {
	$menus = wp_get_nav_menus();
	
	$field[ 'choices' ] = array();
	foreach( $menus as $menu ) {
		$field[ 'choices' ][ $menu->term_id ] = $menu->name;
	}
	
	return $field;
}


add_filter( 'the_content', 'dcwd_display_menu' );
function dcwd_display_menu( $the_content ) {
	if ( ! is_single() ) { return $the_content; }
	
	$menu = get_field( 'menu' );
	if ( ! empty( $menu ) ) {
		//printf( '<p>Menu: %s</p>', $menu );
		return $the_content . wp_nav_menu( array( 'menu' => $menu, 'echo' => false, 'theme_location' => '__no_such_location', 'fallback_cb' => false ) );
	}
}


// Add the ACF field group with the select field type.
add_action( 'acf/init', 'dcwd_add_menu_field_group' );
function dcwd_add_menu_field_group() {
	if ( function_exists( 'acf_add_local_field_group' ) ) {
		acf_add_local_field_group(array(
			'key' => 'group_639357e36d7b1',
			'title' => 'Menu',
			'fields' => array(
				array(
					'key' => 'field_639357e42606e',
					'label' => 'Menu',
					'name' => 'menu',
					'type' => 'select',
					'choices' => array(
						'one' => 'One',
					),
					'return_format' => 'value',
				),
			),
			'location' => array(
				array(
					array(
						'param' => 'post_type',
						'operator' => '==',
						'value' => 'post',
					),
				),
			),
		));
	}
}