Case 1: Multi-level categories.

In SQL, you can do something like this.

How about the code?

To get all the recursive children of Food, you could fetch
SELECT * FROM `categories` WHERE `depth` = 1 AND WHERE `parent_id` = 1
Then you will get array of all the level 2 category, to get the next level you could do
SELECT * FROM `categories` WHERE `depth` = 2 AND WHERE `parent_id` IN (34, 35)
After you know how to get those, you actually can combine these statement straight to get the level 2
SELECT * FROM `categories` WHERE `depth` = 2 AND WHERE `parent_id` IN (SELECT `id` FROM `categories` WHERE `depth` = 1 AND WHERE `parent_id` = 1)
Finally you could combine them to get the deepest depth first, and then loop to get all sub of Food. Or another way is by using JOIN, but it will be very very complicated and less readable even though it's faster than subqueries.
BUT IT ALL DEPENDS ON THE PREVIOUS SYSTEM OR TEAM OR LEAD OR CLIENT

Case 2: Separate configuration for each users.

In SQL, you can do something like this.

Case 3: A product has two types of payment method with different logic.

In SQL, you can do something like this.

How about the code?

For simplicity, it's basically like this

class Foo
{
    protected $bankList = [
        "lorem bank" => "LoremBank",
        "ipsum bank" => "IpsumBank",
    ];

    public function getPayment(): PaymentMethod
    {
        return new $this->bankList[$this->payment_type]($this->payment_id);
        // return new $this->bankList['lorem bank'](3);
        // return new LoremBank(3);
    }
}

Which later return either Object of Class LoremBank or IpsumBank which both have the same interface (PaymentMethod), so that later the programmer could call $payment->pay($debitInformation) with different logic (different API or different cost charged)

Case 4: OAuth ?

In SQL.