On the question of the relationship between the permissibility of modeling contractual structures and freedom of contract

Contracts are quite an important legal structure, since almost all legally significant relations are built on their basis. Despite the importance of this topic, there are still a number of problems that need to be solved, not only in theory, but also in practice. So, one of the problems is the question of the relationship between freedom of contract and the permissibility of its modeling, since these two constructions are quite close in essence, but they need to be able to distinguish correctly.