Is it normal that the backend sends raw data to the front?

Question

Backend

I am not very strong in databases and therefore the question has arisen, since such situations have not been encountered before, either it seems to me, or there were such projects.
The bottom line is that the backend sends "raw data" to the project, that is, in order to build a list (category) of products, I need to blind at least three tables from different queries: I
request, for example: localization, menu, and some other objects with a set of different fields.
Then, using IDs, I begin to design Lego-Menu, finding connections between different objects.
And that's just the product categories. In the project, as far as it seems to me, there is not a single data object to simply request and display on the screen. Each received object must be compared to some other object, comparing their ID links in order to get the whole picture.
Do you think the situation is normal? Is the backend working correctly?
If it was I who relaxed and got used to beautiful data from the backend while working on different projects, then another question follows from this, why do I need a backend on this project? I can do that too, maybe not SQL, but at least in mongo.
I will be very grateful for your answers, your opinion is very important to me :)