here is some update for whom it can be interesting. I made setting page with minimum and maximum title length checking

<?php
/*
Plugin Name: Force Post Title
Plugin URI: https://www.jpsays.com
Description: Forces user to assign a Title to a post before publishing 
Contributors: j_p_s
Author: Jatinder Pal Singh
Version: 1.2
Author URI: https://www.jpsays.com/
*/ 
function force_post_title_init() 
{
  wp_enqueue_script('jquery');
}
function force_post_title() 
{
    $min=get_option('title_page_fields')[title_min];
    $max=get_option('title_page_fields')[title_max];
  echo "<script type='text/javascript'>\n";
  echo "
  window.onload = function() {
  jQuery('.editor-post-publish-panel__toggle').mouseover(function(){
    console.log('run');
		var testervar = jQuery('.editor-post-title__input')[0];
		if (testervar.value.length >= ".$min." && testervar.value.length<=".$max.")
		{
		    jQuery('.editor-post-publish-panel__toggle')[0].disabled=false;
			//console.log('return true '+testervar.value.length);
		}
		else
		{
		    jQuery('.editor-post-publish-panel__toggle')[0].disabled=true;
			alert('Заголовок должен быть от ".$min." до ".$max." символов.\\nСейчас '+testervar.value.length);
			//console.log('return false');
		}
  	});
  }";
   echo "</script>\n";
}
	
function page_settings() {
 echo '<nodiv class="wrap"><h2>Настройка заголовка</h2>';
 
 echo '<form method="post" action="options.php">'; 
 settings_fields('title_page_fields');                  
 do_settings_sections('force_post_title_settings.php');                
 submit_button();                                  
 echo '</form>';
 echo '</nodiv>';
}

add_action('admin_init', 'force_post_title_init');
add_action('add_meta_boxes', 'force_post_title');

add_action('admin_menu', 'add_admin_menu');
function add_admin_menu() {
 add_options_page(
 'Настройка заголовка',
 'Настройки заголовка',
 'edit_posts',                               
 'force_post_title_settings.php',                       
 'page_settings'                             
 ); 
}

function title_page_fields() {
	register_setting('title_page_fields', 'title_page_fields','validate_settings');  
	add_settings_section(
		'snap_section_id',                              
		'Настройки плагина force title page',
		'',                        
		'force_post_title_settings.php'                                     
	);	
	    add_settings_field(
		'title_max',                        
		'Максимальный размер заголовка',
		'custom_html_file_callback',                         
		'force_post_title_settings.php',                                   
		'snap_section_id',
				array( 
			'id' => 'title_max', 
			'title' => 'Максимальный размер заголовка',
			'option_name' => 'title_page_fields',
			'title_max' =>''
		)
	);
	add_settings_field(
		'title_min',                        
		'Минимальный размер заголовка',
		'custom_html_file_callback',                         
		'force_post_title_settings.php',                                   
		'snap_section_id',
				array( 
			'id' => 'title_min', 
			'title' => 'Минимальный размер заголовка',
			'option_name' => 'title_page_fields',
			'title_min' =>''
		)
	);
}
add_action('admin_init', 'title_page_fields');

function custom_html_file_callback($val) {
	extract( $val );
	$option_name = 'title_page_fields';
	$o = get_option( $option_name );
	$o[$id] = esc_attr( stripslashes($o[$id]) );
	echo "<input 
		type='text' 
		name='".$option_name."[$id]' 
		id='$id' 
		value='$o[$id]' />
	<br>";
}  

/*
 * Функция проверки правильности вводимых полей
 */
function theme_validate_settings($input) {
	return $input;
}

?>

Hello,

It’s possible add a functionality the required 50 character on title before to post?

The same feature for excerpt of post?

https://www.ads-software.com/plugins/force-post-title/

Works this plugin also with BBpress?

https://www.ads-software.com/extend/plugins/force-post-title/