You can create the component, then you get something like:

<?php
 
namespace App\View\Components;
 
use Illuminate\View\Component;
 
class Sidebar extends Component
{
    public int $articleCount = 0;
    public int $categoryCount = 0;
    public int $commentsCount = 0;

    public function render() {
    
        $this->articleCount =  Article::count();
        $this->categoryCount =  Category::count();
        $this->commentsCount =  Comment::count();
        return view('components.sidebar')
    }
}

With a component view like:

<ul class="list-group list-group-flush">
	<li class="list-group-item">
		<a class="{{ request()->routeIs('dashboard.articles*') ? 'active' : '' }}" href="{{ route('dashboard.articles') }}">
			Articles
			<span class="badge">{{ $articleCount }}</span>
		</a>
	</li>
	<li class="list-group-item">
		<a class="{{ request()->routeIs('dashboard.categories*') ? 'active' : '' }}" href="{{ route('dashboard.categories') }}">
			Categories
			<span class="badge">{{ $categoryCount }}</span>
		</a>
	</li>
	<li class="list-group-item">
		<a class="{{ request()->routeIs('dashboard.comments*') ? 'active' : '' }}" href="{{ route('dashboard.comments') }}">
			Comments
			<span class="badge">{{ $commentsCount }}</span>
		</a>
	</li>
</ul>

And use it in your blade file like this

<x-sidebar/>

Small note about what I see in your code but not related to your question:
Article::all()->count(); will load all the articles and execute a count on that collection. This will populate all the models can use a lot of memory and request time.
But Article::count(); will execute a count query and only returns the number without creating all the models in memory.