Are you actually willing to pay for an email provider that don't support SMTP and IMAP?

IDK about Protomail, but Fastmail of course supports these protocols. Happy customer here, as are more than a handful of HNers.

Reply to sibling: Why would anyone call an email provider a walled garden, especially if using your own domain name?!

I pay for Fastmail and I don't even use them (waiting for multi label support) just to ensure they remain an option when they support the feature I need to move away from Google.

Switching from labels to folders has been painful as part of the FastMail transition, but I'm largely glad I made the change. Now my mail is standards-compliant and I don't have to deal with all sorts of crud when I have third party mail clients that don't support Gmail's custom stuff.

I know FastMail is working on JMAP, which ideally will be a new standard that supports labels, but if it takes off, it'll be a number of years before labels is something you can assume a given mail client will support. I use platforms that rarely have official app support (aka, not iOS or Android), so wide standards compliance is a big key.

Legitimate concern.

Yes, because at least then it's obvious how they make money.

It's baffling that people are willing to pay for another walled garden.

For everything else (docs, hangouts, calendar etc.) simply host your own nextcloud. You can also go one step further and run a searx instance and you wont even have to rely on Google search (well, still kind of) anymore.

You can also host your own inbound mail, and use gmail for sending. You can add your personal domain email as a "send mail as" entry on gmail, and configure your personal email to use Google's smtp servers. That way you avoid issues with your domain's IP not being trusted by other mail servers.