How to use WooCommerce if the product is user generated?

Question

PayPal

There is a site where the product is formed by a registered user. That is, there are no pre-added products on the site.
For example, Vasya has registered and wants to order a food delivery consisting of several ingredients. He adds 4 more smoothies to this menu and presses the "order" button. It is redirected to a page with information on its order and cost. Then Vasya presses "order" and pays for the purchase online, always through PayPal PLUS.
The menu itself, for example, costs 1000 rubles. Smoothies for 250 rubles each. Only 2000 rubles.
The trick is that the menu changes once a week, smoothies too (and the price of all this too). So next week it might be different. There are also a bunch of different settings, such as, for example, the delivery of such food weekly (subscription), bring the same thing only for two (twice as much), and so on. Which also adjusts the order amount.
All dishes, prices, etc. are formed in wordpress by the hands of an administrator without WooCommerce, added to custom database tables, and so on. That is, the entire interface is implemented from scratch without plugins.
And in general, WooCommerce itself is connected only in order for PayPal PLUS payment to work correctly.
Now the essence of the question: how to connect WooCommerce and configure it to process such orders? Or how to connect PayPal PLUS (not to be confused with PayPal Standard, which connects in a few clicks ) without WooCommerce (the documentation is incomplete and does not dedicate the developer how to connect this service from scratch).