Hello everyone,
I have now signed up for Proton Plus for €4.99 per month. It includes a personal domain. The setup worked just like you would expect from Google Workspace. First identify that the domain belongs to you and then enter the MX records in the DNS and you’re done. The desktop program for Windows is clean, without annoying advertising or other unnecessary stuff. The program includes the mail client and the calendar. In Android there are two different apps, the calendar can also be displayed as a widget. Emails are sent quickly and reliably. Forwarding from other email addresses such as Gmail is reliable. I will test the whole thing thoroughly over the next few weeks. So far, so good.