Enjoying groceries bought on Shabbat

I was thinking of two more branches to permit, I would love to hear your opinion.
1. Halacha commentary (Shi”ch a’ d”a echat) – What they prohibited in the Moshe is only in the matter of making a change to the body of the object (but it concludes that the Torah prohibitions must be stricter. And here there is a rabbinical prohibition on buying, a rabbinical prohibition in our community, which is nothing but Carmelite, and a Torah prohibition if they use a vehicle to transport the groceries).
2. Permit based on ‘multiplicity in classes’ – They do not do any special work for us, because the purchase is made in one go (perhaps with one payment on a credit card), and so is the transportation.

I saw that a halakha was written in my case regarding enjoyment from an act that did not change the body of the thing as follows:

Some say that if the work did not change anything in the body of the object, such as transferring an object from public to private ownership, there is no prohibition on the object, and it is permissible to enjoy it on Shabbat in private ownership (Rabbi Yonah and Ritva). The same is true regarding foods brought in a vehicle on Shabbat, since no change was made to the foods, there is no prohibition on them. Some say (Tuss, Ramban and Rishba) that there is no difference between the types of work, and even if the work did not change anything in the foods, it is forbidden to enjoy the foods that were brought in with the prohibition. In fact, one should initially be strict, and in times of need one can rely on the lenient ones, especially when the matter is done by mistake.[6]
If another permissible action was performed through the work, it is permissible to enjoy it. For example, if you fix a hammer on Shabbat, it is forbidden to use it even for permitted purposes, such as cracking nuts. And if someone passes by and cracks nuts with it, it is permissible to enjoy the nuts, since the act of cracking itself is not forbidden.

If you open a door that is locked by a prohibition, such as using a magnetic card – some say that it is forbidden to enter through that opening, since it was opened by a prohibition. Some say that it is permissible, because opening the door did not create anything new, but only removed something that prevented entry. In retrospect, in times of need, it is permissible to ease up. If you open a refrigerator door and a light comes on there, it is permissible to take food out of the refrigerator (Ei’ above 17:9).

If a Jew who violates Shabbat approaches an electric door and thereby opens it, it is forbidden to enter through it. Only in times of need can this be eased up. If a Jew passes by and the door opens unintentionally, it is permissible to enter through it (Ei’ above 17:11).[7]

Would it also be correct here to say that buying groceries is an act that did not change the substance of the matter and that it would be possible to make concessions based on this?

It is possible, but this is a method that is too narrow for the law and has contradictions with some of my doctrines. In particular, on Shabbat, a bad work was performed, and yet it was forbidden. In other words, changing the place is like changing an object (and in my column on performing the work, I explained that it is a change in the world. Entropy).
Regarding the multiplication of the shiurim, this is an interesting comment, but for the law, it is not a matter for discussion. There, we are talking about a work that is done with permission (such as cooking for the sick, or harvesting for the Omer) that is multiplied. Here, it is entirely forbidden. And there, some Rishonim also hold that it is forbidden by the law.