Disable "route model binding"

in your controller method, dont type hint the model

Use id, on your routes instead of the model name books/{id} instead of books/{book} and then as @snapey says, don't type hint in your controller.

public function show($id)

Instead of

public function show(Book $book)

@martinbean I understand that you are right, but I could not fix the error (I hope it is a error). Perhaps I need to do the language.edit route in another project that doesn't have language settings. Actually, I got really carried away with "route model binding" and decided that if I have many resource routes and only language.edit doesn't work with ID (it seemed to me that it works like "route model binding"), then it's better to do it "correctly" - the model name and route parameter should be different, then Laravel will 100% not substitute the model instead of ID. Thank you again for your help.

@martinbean The story of my problem. In my project, I had a lot of almost similar tables (clients, contracts, ... languages, ... users) and all these tables had their own controller. I passed the IDs to the methods: client, contract, ... language, ... user, and in the controller I received and processed the models (Language $language). All the controllers were similar, some had additional logic, but if I needed to make some general change, I edited all the controllers (again, I'm a beginner) and constantly thought about OOP! One day I couldn't stand it anymore and decided to rewrite almost the entire backend. I made a basic controller:

class BaseController extends Controller
{
    protected Request  $request;       // The request instance
    protected ?string  $front_theme;   // Frontend theme
    protected ?string  $back_theme;    // Backend theme
    protected Language $current_lang;  // Current content language

    protected string   $itemModel;     // Model of the current item
    protected string   $itemRequest;   // Request validation for the current item
    protected ?bool    $editRequest;   // EditRequest differs from Request (null - use the basic Request) 
    protected ?string  $whoseCategory; // The name ('Post') of the item for which this category was created
    protected ?string  $categoryModel; // Item category model
    protected bool     $itemHasOwner;  // The item has an owner
 
    public function __construct(Request $request)
    {

        $this->request       = $request;
        $this->front_theme   = Cookie::get('front_theme');
        $this->back_theme    = Cookie::get('back_theme');      
        $this->current_lang  = $this->setContentLang($request->language);

        $this->editRequest   = false;
        $this->whoseCategory = null;
        $this->categoryModel = null;
        $this->itemHasOwner  = false;
     
    }
// Сontroller methods for processing resource routes

And then most of my controllers got rid of the code altogether:

class MemberController extends BaseController
{
    public function __construct(Request $request)
    { 
        parent::__construct($request);
        $this->itemModel     = Member::class;
        $this->itemRequest   = MemberRequest::class;
    }
}

or, if there is additional logic:

class ClientController extends BaseController
{
    public function __construct(Request $request)
    { 
        parent::__construct($request);
        $this->itemModel     = Client::class;
        $this->itemRequest   = ClientRequest::class;
        $this->itemHasOwner  = true;
    
    }

    protected function itemQuery(Builder $query): void
    {

        if (!Auth::user()->isAdmin()) {
            $query->where('user_id', Auth::user()->id);
        }

    }

    public function store(): RedirectResponse
    {

        $response   = parent::store();
        $request    = app($this->itemRequest);
        $item       = $request->validated();
        $latestItem = $this->itemModel::latest()->first();
    
        if (isset($item['user_id'])) {
            $latestItem->update(['user_id' => $item['user_id']]);
        }
    
        return $response;
    }
}

But I was unable to make a universal method that receives different models. I naively hoped for:

   public function index(Model $item): View  

You understand that I was expecting disappointment here. This is a mistake. And then I decided that my problem was solved only by transferring the ID:

public function index(int $itemId): View 

Everything worked very well until I started testing the language.edit route. Everything worked very well until I started testing the language.edit route. It returned a 404 error without entering either the controller or the middleware. I tried to manage it even in the RouteServiceProvider. I couldn't change anything, so I abandoned the resource routes for the Language model and wrote custom ones. I was already afraid of "route model binding" and therefore used the {id} parameter instead of {language} in the routes. The language.edit route started working as expected. It was then, under the influence of (perhaps a misunderstanding of) route model binding, that I changed the route parameter in all routes:

...*LanguageController*::class)->parameters(['language' => 'id']);

But I did it after I addressed the community in this post.