Making a raw request body look like the form data is not possible because, as you probably know, JSON can include nested objects, so the structure itself is more complex.
How does it work in OAS/Swagger? Can you share a screenshot?
There are two options that you could explore in Postman:
This allows you to define a schema (with OpenAPI/Swagger). I admit, this is a rather formal way of specifying a description of the parameters, but I wanted to point it out anyway.
You can then link the schema and the collection in Postman.
You can find on YouTube a short tutorial created by me explaining how this works: https://www.youtube.com/watch?v=hSX7Dcjy000
I hope one of these two options provide a temporary solution.