Like button not recording likes in the back end

Button successfully links back to current blog page but the likes are recording in the back end, what am I doing wrong here?

views

def BlogLike (request, slug):
        post = get_object_or_404(BlogPost, id=request.POST.get(slug))
        post.likes.add(request.user)
        return render(request, 'viewblog', {'post': post})

urls

path('view-blog/<slug:slug>/', views.ViewBlog, name='viewblog'),
path('like/<slug:slug>', views.BlogLike, name='likepost'),

html

<form action="{% url 'viewblog' blog.slug %}" method="POST">
    {% csrf_token %}
    <button class="btn btn-outline-secondary rounded-0 custom-button" id="like" type="sumbit" name="blog_id" value="{{ blog.slug }}">Like</button>
</form>   

EDIT

class BlogPost(models.Model):
    title = models.CharField(max_length=100, null=False, blank=False, default="",)
    text = RichTextUploadingField(null=True, blank=True, default="text")
    featured_text = models.TextField(max_length=550, null=True, blank=True, default="text")
    image = models.ImageField(null=True, blank=True, upload_to="images", default="default.png")
    date = models.DateField(auto_now_add=True)
    published = models.BooleanField(default=False)
    featured = models.BooleanField(default=False)
    slug = models.SlugField()
    likes = models.ManyToManyField(User, related_name='likes')
    
    def save(self, *args, **kwargs):
        self.slug = self.slug or slugify(self.title)
        super().save(*args, **kwargs)

    def __str__(self):
        return self.title

This is my functional code.

views

def BlogLike (request, slug):
        post_id = request.POST.get('blog-id')
        post = BlogPost.objects.get(slug=post_id)
        post.likes.add(request.user)
    
        return HttpResponseRedirect(reverse('viewblog', args=[post_id]))

html

<form action="{% url 'likepost' blog.slug %}" method="POST">
    {% csrf_token %}
    <button class="btn btn-outline-secondary rounded-0 custom-button" id="like" type="sumbit" name="blog-id" value="{{ blog.slug }}">Like<i class="fa-solid fa-heart"></i></button> - {{ blog.total_likes }} Likes
</form>  

urls

 path('like/<slug:slug>', views.BlogLike, name='likepost'),

models

likes = models.ManyToManyField(User, related_name='likes')

  def total_likes(self):
        return self.likes.count()   #this is to count amount of likes a post has.