[Table]
    public class Product
    {
        [Key]
        public int Id { get; set; }
        public string Name { get; set; }

        public List<CategoryProduct> CategoryProducts { get; set; }
    }

    public class CategoryProduct
    {
        public int CategoryId { get; set; }
        public int ProductId { get; set; }
        
        public Category Category { get; set; }
        public Product Product { get; set; }
    }


    [Table]
    public class Category
    {
        [Key]
        public int Id { get; set; }
        public string Name { get; set; }

        public List<CategoryProduct> CategoryProducts { get; set; }
    }

        public async Task CreateProduct(Product dto)
        {
                await ctx.Products.AddAsync(dto);
                await ctx.SaveChangesAsync();
        }

{
            "id": 0,
            "name": "Gräff Stettin",
            "categoryProducts": [{
                    "categoryId": 1,
                    "productId": 1,
                    "category": {
                        "id": 1,
                        "name": "Drinks"
                    }
                }, {
                    "categoryId": 2,
                    "productId": 1,
                    "category": {
                        "id": 2,
                        "name": "Alcohol"
                    }
                }
            ]
        }

INSERT INTO "Category" ("Id", "Name")
VALUES (@p0, @p1);