I've been looking at mail providers too, and it's starting to look there are no real alternatives. Not just in Europe, but worldwide. I've been a happy user of Fastmail for quite some time now, and it's sad the the current geopolitical situation pressures me into migrating away.
The alternative that's looking best to me so far is Kolab Now. I don't see a lot of user reviews of it on Reddit though, or anywhere else, so it seems to not be very popular at first sight. That's perhaps not a good sign.
In any case I'm planning on trying it out for a while, with a domain I don't use it all that often, before deciding to migrate to it.
Doesn’t seem to support on-the-fly aliases for sending, requiring instead to set it up in advance. I use a custom mail per website/contact workflow, and with FM any reply uses whatever alias I used to receive the mail, with the option to change it to whatever I want without extra steps.
The alternative that's looking best to me so far is Kolab Now. I don't see a lot of user reviews of it on Reddit though, or anywhere else, so it seems to not be very popular at first sight. That's perhaps not a good sign.
In any case I'm planning on trying it out for a while, with a domain I don't use it all that often, before deciding to migrate to it.