I've been a Proton user for a few years but I'm not resubbing this year. Trust issues aside, it seems like you are paying premium for a service that offers encrypted storage as the only pratical advanced while being a bit behind on usability.

Let me put some emphasis on storage here. The SMTP protocol was not created with privacy in mind. As soon as a message leaves a mailbox and start traversing through the internet it will be laid bare to all the SMTP relays along the way. Of course there are stuff people stapled on top of it like PGP or MIME encryption but the headers are still laid bare.

On the other hand I'm also not keen on the idea that a disgusting company like Google or Microsoft can read my messages and sell my data to their customers.

Trigger warning, the rest is a self hosting junkie inane ramblings. Most people would be better just using Proton or just not using e-mail at all:

The solution I found was to subscribe to a non kyc, privacy and bitcoin friendly VPS provider like 1984 hoting and setup an OpenBSD server with OpenSMTPd, Spamd and Dovecot. I've setup all the proper access rights plus DNS entries to make my server clean legit. Got certificates from Letsencrypt to encrypt data in transit. I've TLSd everything.

This runs on the bare minimum hardware offer which costs the equivalent 5 cuckbucks a month or less if you sign long term. Although not perfect I used my own ISO and encrypted the root file system. While 1984 can still do stuff like read the VM memory contents they would have a difficult time probing the disk contents. Not impossible but still hard.

So I can now read and send messages with some simple IMAP client including Mutt. A very simple setup but I still want some fluff right?

On my end I'm self hosting an iRedMail setup with all the fluff you can expect from modern e-mail providers like calendars, webmail, activesync and so on. With plenty of memory and cpu available I could also install sophisticated spam and malware prevention software.

I then told my local postfix that all mail should be relayed through my VPS and told my VPS that relaying from the server on my home network is allowed. I also installed a piece of software called Fetchmail that connects to the VPS IMAP server and syncs the data there to the local mailboxes.

mail arrives -> 1984 Dovecot -> Fetchmail -> Home Dovecot sending mail -> Local postfix -> relays to 1984 postix -> destination

SMTP TLS is enforced therefore 1984 are unable to see headers. Fetchmail polls every minute so mail never stays too long on VPS.

Now if I ever turn off my home server the remote server will hold on to those messages until fetchmail runs again. In that case I can also use Mutt to read messages directly from the relay server.

I'm pretty sure some people would say its too complicated and unintelligible while some would point out situations where someone could probe my messages but everything is a tradeoff. I now own my data and I'm quite happy about it.