CI4: Handling model errors

I'm a bit confused on how to properly handle errors that happen in a model:

• According to the "Error Handling" part of documentation model should throw an exception on error
  
• CodeIgniter4 in its Model returns false without throwing an exception on validation error
  

So I guess my questions are:

1. When Model should simply return false and when should it throw an exception?
   
2. If I decide to return false in my custom model method, can I make my custom error message available over Model:errors() for a controller?
   
3. As CodeIgniter4 seems to mix two ways of handling errors should my controller always do something like:
   try {    $post = $postModel->insertWithAttachments($data, $attachments);} catch (\Exception $e) {    return redirect()->back()->withInput()->with('errors', $e->getMessage());}if (!$post) {    return redirect()->back()->withInput()->with('errors', $postModel->errors());}This seems a bit complex as for a single model call.