(C#) Nested schema properties treated as Dictionary<string, object>

[carensbak]

Hello Kiota team,

I've tried to generate a SDK from the Nutanix 4.1 VMM OpenAPI specification, found at
https://developers.nutanix.com/api-reference?namespace=vmm&version=v4.1

I am trying to use the (POST) https://{pc-ip}:9440/api/vmm/v4.1/content/templates/{extId}/$actions/deploy endpoint.

Expected behaviour

When creating the request, I would expect the nested objects/schemas to have their specific types as properties, rather than the Dictionary<string, object>. In this case I would expect the OverrideVmConfigMap property to be an object that looks like this:

public class OverrideVmConfigMap 
{
    public string? Name { get; set; }
    public int? NumSockets { get; set; }
    public int? NumCoresPerSocket { get; set; }
    public int? NumThreadsPerCore { get; set; }
    public int? MemorySizeBytes { get; set; }
    public Nic? Nics { get; set; } //another nested object
    public GuestCustomizationParams? GuestCustomization { get; set; } //another nested object
}

As per the OpenAPI specs Schmea section (Line 47,498):

    vmm.v4.1.content.VmConfigOverride:
      type: object
      properties:
        name:
          maxLength: 80
          minLength: 1
          type: string
          description: VM name.
          example: LinuxServer_VM
        numSockets:
          minimum: 1
          type: integer
          description: Number of vCPU sockets.
          format: int32
          example: 21
        numCoresPerSocket:
          minimum: 1
          type: integer
          description: Number of cores per socket.
          format: int32
          example: 36
        numThreadsPerCore:
          minimum: 1
          type: integer
          description: Number of threads per core.
          format: int32
          example: 71
        memorySizeBytes:
          minimum: 1
          type: integer
          description: Memory size in bytes.
          format: int64
          example: 61
        nics:
          maxItems: 2147483647
          minItems: 0
          type: array
          description: NICs attached to the VM.
          items:
            $ref: '#/components/schemas/vmm.v4.1.ahv.config.Nic'
        guestCustomization:
          $ref: '#/components/schemas/vmm.v4.1.ahv.config.GuestCustomizationParams'
      additionalProperties: false
      description: Overrides specification for VM creation from a template.

And the Redoc:

Actual behaviour

The class only has a singular property, public IDictionary<string, object> AdditionalData { get; set; }, and not the nested types.

This would require me to manually put in the KeyValue pairs, and it seems like a very brittle solution.

OverrideVmConfigMap = new()
{
    AdditionalData = new Dictionary<string, object>()
    {
        { "name", req.HostName },
        { "numSockets", 1 },
        { "numCoresPerSockets", options.BaseCpus + (int)Math.Floor((double)req.UserCount / (double)options.UsersPerExtraCpu) },
        { "memorySizeBytes", (options.BaseMibRam + (req.UserCount * options.ExtraMibRamPerUser)) * 1024 * 1024 },
    }
}

Repro steps

1. Download the Nutanix 4.1 VMM OpenAPI spec from the top of the page at https://developers.nutanix.com/api-reference?namespace=vmm&version=v4.1
2. Generate the SDK -
   I've used this script to generate the client:

#!/bin/bash
"$PROJECT_ROOT"/metadata/OpenAPI/kiota.exe generate \
   --language CSharp \
   --class-name NutanixVmClient \
   --output "$PROJECT_ROOT"/src/<project>/GeneratedClients \
   --clean-output \
   --openapi "$PROJECT_ROOT"/metadata/OpenAPI/Nutanix-VM-41.yaml \
   --exclude-backward-compatible 

3. Use the generated SDK

Is this me misunderstanding something? Are the nested types / schema references not supposed to be generated as models?
I'm still new to Kiota, so any help / pointers in the right direction would be much appreciated 🙏

Additional Info / steps I've tried

Versions used

Kiota: 1.27.0+278d4c17bfbc9fff8d8a1618bd95b43b1e3f7f4d
.NET SDK: 9.0.302

IAdditionalDataHolder

The class implements the IAdditionalDataHolder interface.
I've tried adding the --additional-data false to the script, which entirely removes the IDictionary<string, object> AdditionalData property, but it does not turn the nested types into properties.