paged > max_num_pages won't throw 404

I've created new page in WP administration called Blog and created custom page template for it. In the template, I have a simple paged custom query.

$query = new WP_Query(array( 'post_type' = 'post', 'posts_per_page' = 1, 
'paged' = $paged ));

Everything seems to look ok, except when I manually type bigger page number than is available after the '/page/' part of url. The page won't throw a 404 error but will render the page as normal without the custom loop. Is it normal behaviour? If so, how should I throw the 404 template page?

Also, I have one sub question:

Is it possible, to create custom theme page, without the need to create the page in the wordpress adminstration? In most cases I don't even use the content of the page and leave it empty. Then if someone will delete the page, or change the page slug, part of website can be broken.

Is there more fool proof and more administrator friendly solution?

PS: here is the full page-blog.php source code:

div id="primary" class="content-area"
    main id="main" class="site-main"

        h1?=get_theme_mod('crochelou-blog-main-headline') ?span class="sub-headline"?=get_theme_mod('crochelou-blog-sub-headline') ?/span/h1
        section id="page-container"
        nav id="blog-nav-wrapper"?php
            wp_nav_menu( array(
                'menu_id'        = 'category-menu',
                'menu' = 'category-menu'
            ) );
        ?/nav
            ?php

            $query = new WP_Query(array( 'post_type' = 'post', 'posts_per_page' = 1, 'paged' = $paged )); ?


            section id="main-blog-loop"?php
                if($paged  1){ ?
                    a href="?= get_pagenum_link($paged - 1) ?" class="pagination-arrow arrow left arrow-left prev"/a
                ?php }

                ?div class="wrapper articles"
                    ?php 
                    while($query-have_posts()): $query-the_post(); ?

                    article class="crochelou-card blog"
                        div class="blog image" style="background-image: url('?=esc_url(the_post_thumbnail_url('medium'))  ?')"/div
                        div class="categories"?php
                            $categories = get_the_category();
                             foreach($categories as $category){ 
                                 $name = $category-name;
                                 $link = get_category_link($category-term_id); ?
                                 a href="?= $link ?" class="catgory"?= $name ?/a
                            ?php
                             }
                        ?/div
                        span class="date"?= get_the_date('d') . '\\' . get_the_date('m') . '\\' . get_the_date('Y') ?/span
                        h4 class="headline blog"a href="?= get_the_permalink() ?"?= get_the_title() ?/a/h4
                        div class="perex excerpt"?php the_excerpt(); ?/div
                        a class="link read-more" href="?= get_the_permalink() ?" číst../a
                    /article



                    ?php endwhile;
                    ?
                /div?php
                if($paged  $query-max_num_pages){ ?
                    a href="?= get_pagenum_link($paged + 1) ?" class="pagination-arrow arrow right arrow-right right"/a
                ?php }

                ?
            /section



                ?php if($paged  $query-max_num_pages){  ?
                    div id="blog-pagination"
                        nav class="pagination"
                            ul
                                ?php 
                                for($i=1; $i = $query-max_num_pages; $i++){

                                    if($i === $paged){ ?

                                    span class="current"?= $i ??php if($i  $query-max_num_pages){ echo ','; } ?/span

                                    ?php }else{ ?

                                    a href="?= get_pagenum_link($i) ?"?= $i ??php if($i  $query-max_num_pages){ echo ','; } ?/a

                                    ?php }

                                }
                                ?
                            /ul
                        /nav
                    /div
               ?php     }       


            ?
            !-- THIS WILL JUST RENDER 'ABOUT ME' TEST FROM ADMINISTRATION --
            div class="separator"/div
            ?php $page = get_page_by_path( 'o-mne' ); ?
            article id="about"
                h3 class="title"?= $page-post_title ?/h3
                ?php 
                $content = $page-post_content;
                $content = apply_filters('the_content', $content);
                $content = str_replace(']]', ']]gt;', $content);
                ?
                div id="about-content"?= $content ?/div
            /article



        /section
    /main!-- #main --
/div!-- #primary --