Twilio. And if you use Teams, it’s almost trivially easy to set up Asterisk as an SBC for direct routing. Teams can handle auto attendants, call queues, voicemail with transcription, lots of other features. Not saying it’s perfect or does everything, but it will do what most people need pretty well and save you from needing to buy phones or pay for SIP software phones.
We have people in the UK, US, and a few other countries in Europe. I have it set up so we have main “switchboard” numbers in the US and UK, and everyone has an extension. I don’t buy DIDs for everyone. It’s not a perfect system, but it’s meeting our requirements.