Returning custom objects with asp.net core api errors

I am using asp.net core 2.1, I need to emulate some existing behavior when returning errors in an api whereby the response includes a custom object:

return this.BadRequest(
    new ApiError
    {
        // The corresponding integer response code.
        Status = StatusCodes.Status400BadRequest,
        // The matching short text code.
        Code = "BadRequest",
        // A detailed context specific message.
        Message = "Some message"
    });

My question is, asp.net core brought the Microsoft.AspNetCore.Http.StatusCodes class with integer fields that indicate the response codes, however the field names are not something I want to expose for example by Code = nameof(StatusCodes.Status400BadRequest).

What is the modern means to generate the response description BadRequest in this case without magic strings?

I could use System.Net.HttpStatusCode.BadRequest and nameof(System.Net.HttpStatusCode.BadRequest) however that seems to ignore newer conventions?

I am not trying to convert return types, the controller and action signatures are already well defined. I want to ensure I am using a concise means to accommodate existing consumers that expect an object with the fields required, and I want to do this without magic strings or multiple unrelated classes if possible.

I imagine the use case is more common than not and more elaborate facility exists to accomplish this?