well, deepgram might be the fastest among cloud-dependent APIs, like Speechmatics and Assembly AI mentioned above. -but- it cannot be faster than local or smaller models as you mentioned.

Among local solutions, Whisper SDK doesn't support streaming, I haven't seen any good workarounds or successfully implemented it. VOSK, DeepSpeech, Kaldi, et al were good once upon a time... Picovoice seems to be doing well.

I was planning to work on this: https://picovoice.ai/blog/chatgpt-ai-virtual-assistant-in-py... using Eleven Labs and Cheetah. Hope I can crave some time