Great point, well articulated.
Our product does not officially support Exchange (mostly due to dev bandwidth limitation :( ) BUT if you can subscribe to your Exchange calendar in a Google Calendar (linked to any Google Account) then you can try Hera without any frictions because Hera will be able to pull your meetings from the Exchange calendar.
The trouble with this method is that it creates a publicly-accessible, unauthenticated feed of my calendar and all the event data in it. I don't deal in a lot of particularly sensitive trade secrets, so I'm less concerned than others on this thread about the notes being unencrypted in your cloud. Encryption would be great, but I have a reasonable expectation that you're not just letting anybody who finds it scoop up your whole database. But that's what publishing a calendar feed does. I can't leave an open door to the internet (however obscure) to all the potentially confidential information that someone might send me as part of an event. I'll have to wait for "real" exchange support.
I've seen resources for that: https://www.howtogeek.com/435975/how-to-show-an-outlook-cale....
Let me know or shoot me an e-mail at bruno at hera dot so if you need any help!