For my company, we are using an hosted offer from Element.io[0].
It works wonderfully, it became a really nice hub of communication, information sharing with dedicated rooms for different stuff (CI/CD, link sharing, planing, etc.) and the service has no downtime I can remember in the past year.
Highly recommended and this funds indirectly the development of Matrix.
How are voice calls?
Edit: looks like there's a 50 user minimum for business plans?
If you host a server yourself you can hook in coturn (it's enabled by the linked playbook by default):
https://github.com/spantaleev/matrix-docker-ansible-deploy/b...