With Livekit you can connect to inbound calls only in the US atm, you'd need other platform for outbound telephony.
It is exactly the platform for orchestration where you can manage STT/LLM/TTS.
For real-time events like call start/end, transcripts, LiveKit emits those via callbacks, you can push them to ServiceNow via webhooks.
For reference architectures, check the docs/Git - they have voice bot templates
you can ask ai in here as well