Depending on requirements, this data is only for viewing and should therefore not be downloaded by the user.
From everything I've researched, there is no ultimate way to prevent a user from getting the data, but rather to increase the difficulty. The idea is therefore to make it difficult for a user to download the data, at least not so easily via developer consoles.
This is the question of whether symmetric encryption is useful for my problem. What other disadvantages or security gaps would result from this?
In general, what is an appropriate way to prevent or make it difficult for users to download restful resources?