Are there any plans to sync with email and calendar providers that are not Google or Microsoft? Perhaps something via CalDav. We are currently using Protonmail.
For email, you should be able to connect with most email providers if you can connect through IMAP.
For calendar, the current options are listed here, but I will be sure to pass your feedback along to the team. Thank you for taking the time to send it to us.
Have a lovely week!