The Exchange 2019 Sizing Calculator was released a few weeks ago.
https://techcommunity.microsoft.com/t5/Exchange-Team-Blog/Announcing-The-Exchange-Server-2019-Sizing-Calculator/ba-p/644180
The calculator is now optimized for Exchange 2019 and has the following updates:
- Improved Virtualisation Support
- Updated SPECint Benchmark
- Support for MetaCache (new feature in Exchange 2019)
- Now has a hard 2TB mailbox database limit
See the link for further details.