How to link to children-children?

Question

Django

Hello!
Django just started learning, ran into a problem. To which I can't find an answer.
I want to implement the following structure:
/library - categories page
/library/$id ​​- subcategories page
/library/page/$id - final page
I made the connection through ForeignKey, it turned out to display categories and subcategories correctly, but there was a problem with the final page. I made a separate model for it and now I can’t display a link to this page. I'm trying to link using the absolute link method:
Model:

models.py

from django.db import models
from django.shortcuts import reverse
from ckeditor.fields import RichTextField

from image_cropping import ImageRatioField
from easy_thumbnails.files import get_thumbnailer


class Groups(models.Model):
    class Meta:
        verbose_name_plural = 'Группы'
        verbose_name = 'группу'

    title = models.CharField(
        max_length=255,
        verbose_name='Заголовок',
        db_index=True,
        blank=False
    )
    description = models.TextField(
        verbose_name='Описание',
        default=None,
        null=True,
        blank=True,
    )
    body = RichTextField(
        verbose_name='Основной текст',
        db_index=True,
        blank=True
    )
    created = models.DateTimeField(
        verbose_name="Время создания",
        auto_now_add=True
    )
    modified = models.DateTimeField(
        verbose_name="Время изменения",
        auto_now=True
    )

    parent = models.ForeignKey(
        'self',
        verbose_name='Родитель',
        related_name='children',
        on_delete='CASCADE',
        default=None,
        null=True,
        blank=True,
    )

    @property
    def count(self):
        self_count = 0
        children_count = 0
        if hasattr(self, 'page_children'):
            self_count = self.page_children.count()
        if hasattr(self, 'children'):
            children_count = len([children.count for children in self.children.all()])
        return self_count + children_count


    def get_absolute_url(self):
        return reverse('group_url', kwargs={'group_id': self.id})

    def get_absolute_url_page(self):
         return reverse('pages_url', kwargs={'pages_id': self.page_children.pages_id})

    def __str__(self):
        return self.title


class Pages(models.Model):
    class Meta:
        verbose_name_plural = 'Страницы'
        verbose_name = 'страницу'

    title = models.CharField(
        max_length=255,
        verbose_name='Заголовок',
        db_index=True,
        blank=False
    )
    body = RichTextField(
        verbose_name='Основной текст',
        db_index=True,
        blank=True
    )
    image = models.ImageField(
        upload_to='library/img/',
        verbose_name='Фотография',
        blank=True
    )
    cropping = ImageRatioField(
        'image',
        '1210x480'
    )
    created = models.DateTimeField(
        verbose_name="Время создания",
        auto_now_add=True
    )
    modified = models.DateTimeField(
        verbose_name="Время изменения",
        auto_now=True
    )
    parent = models.ForeignKey(
        'Groups',
        verbose_name='Родитель',
        related_name='page_children',
        on_delete='CASCADE',
        default=None,
        null=True,
        blank=True,
    )


    def get_image_1210x480(self):
        return get_thumbnailer(self.image, '1210x480')

    def __str__(self):
        return self.title

View:

views.py

from django.shortcuts import render, get_object_or_404
from .models import *


def index(request):
    groups = Groups.objects.filter(parent__isnull=True).all()
    return render(request, 'library/index.html', context={'groups': groups})


def podgroup(request, group_id):
    item = get_object_or_404(Groups, id__iexact=group_id)
    return render(request, 'library/block.html', context={'item': item})


def pages(request, pages_id):
    page = get_object_or_404(Pages, id__iexact=pages_id)
    return render(request, 'library/pages.html', context={'page':page})

Yurly:

url.py

from django.urls import path

from .views import *

urlpatterns = [
    path('', index, name='groups_list'),
    path('<str:group_id>/', podgroup, name='group_url'),
    path('page/<str:pages_id>', pages, name='pages_url'),
]

Page template on which the link should lead to the final page:

block.html

{% extends 'base.html' %}
{% load cropping %}
{% load static %}

{% block title %}
    {{ item.title }} - {{ block.super }}
{% endblock %}

{% block content %}
    <div class="row">
        <div class="col-lg-12 mt-4">
            <div style="background: #3F729B; color: white; font-size: 14px;
                        font-weight: 400; text-transform: uppercase; text-align: center;
                        padding: 15px; border-top-left-radius: 5px; border-top-right-radius: 5px;">
                {% if item.description %}
                    {{ item.description }}
                {% else %}
                    {{ item.title }}
                {% endif %}
            </div>
        </div>
        {% if item.children.count > 0 %}
            <div class="col-sm-12 flex-col">
                <div class="dig-list-group__content">
                    {% for item in item.children.all %}
                        {% if item.count > 0 %}
                            <div class="dig-list-group__element js-link"
                                    data-url="{{ item.get_absolute_url_page }}">
                                    <div class="dig-list__item">
                                        <h4 style="font-weight: 400;">
                                            <a href="{{ item.get_absolute_url_page }}">{{ item.title }}</a>
                                        </h4>
                                    {% if item.description %}
                                        <hr style="background-color: black; height: 2px; width: 80px;"/>
                                        <span>{{ item.description }}</span>
                                    {% endif %}
                                </div>
                            </div>
                        {% endif %}
                    {% endfor %}
                </div>
            </div>
        {% endif %}
{% endblock %}

In this case, attempting to load a page (of subcategories) gives the error "'RelatedManager' object has no attribute 'pages_id''". Tell me what I'm doing wrong or how I should have done it.
Thanks in advance!