Posteo is a very legitimate email provider based in Germany. Your bank is really stupid for flagging and rejecting it, their is absolutely nothing about them that should trigger their systems.

An alternative would be Mailbox, it's very similar to Posteo and I have made good experiences with it.

Why did you switch away from Proton? Most drama surrounding it is very overblown and the consequences of being a large company, not everyone always does everything right who works for them.

I use Tuta with a custom domain name. Never had any issues. About $12 a year.

https://tuta.com/

I've been using Fastmail for a while now, and I like it. Clean interface, good apps, and lots of support for CALDAV (including tasks!). Frankly a much better interface than many other providers. I was also tired of using Thunderbird with my hosting provider's email.

I spent quite a while looking for a good email provider as well. Proton didn't work for similar reasons, and I didn't like having to use the bridge on Linux. I settled on Fastmail as it's cheap, and does what I need (email, calendar, tasks).

I wasn't excited that they have servers in the US (they're an Australian company), but I had to make a compromise to degoogle. "Perfection is the enemy of progress" is a common phrase for me.

I'm interested to see what other opinions come up though.

One with my own domain name attached has always been my go-to because I can migrate to a different provider easily without needing to update all my accounts.

What's the issue with proton?

Purelymail.com … cheap af, just works. I use my own domain and have never had deliverability issues. Support is fast. You’re also under the radar because it’s not a huge outfit.

I've not found a viable replacement for mxroute (I know us based). All the other email services seem to be priced by the number of accounts. I have a bunch of accounts I need to keep separate, some personal and some business. Some accounts have a few aliases as well. But Aliases just don't cut it on their own.

You can stick with Posteo and use email aliases for sites that don't like it

I’ve been using Migadu for last couple years with no issues. All you need is a custom domain.

https://www.migadu.com/

You can bring your own client, but there’s webmail too (requires no JS if I recall) so you can access your inbox from anywhere too.

Mailbox.org seems a decent choice.

I've been using Mailbox.org, both private and for my business, for 5 years now. I have nothing bad to say about them or their service.

Well. I would like to see a referral program! They have a lot of paying customers because of me, but you don't get anything in return.