Is your feature related to a specific framework or general for this extension
No.

Is your feature request related to a problem? Please describe.
There are other AI services that provide APIs compatible with OpenAI interfaces. Now we can change Api Root but many service providers have their own naming of models(Deepseek, for one). Allowing custom model names would greatly enhance the capability to integrate with different AI services.

Describe the solution you'd like
Maybe change the prop type from enum to string?