I just started the process of moving from gmail to an email on a custom domain through https://www.migadu.com/en/index.html. The setup process was pretty painfree and they provide very detailed setup instructions.

I haven't set my gmail to forward to the new email yet. I've spent the last month or so unsubscribing from a lot of email newsletters. Once I get the mail volume down even further, I'll setup gmail to autoforward and then give out my new email to those who need it.

I haven't yet found a Google Calendar substitute but that's lower priority right now.