But before switching email services, do yourself a favor and ditch webmail interfaces first. Pick up a desktop/native email client and switch to IMAP / SMTP.
On MacOS a solid option for us power users is MailMate (https://freron.com/) ... markdown composer, GMail shortcuts, useful bundles, fast, uncluttered, it's basically what I wanted Thunderbird to be. Development on Thunderbird is apparently ongoing too and they just released version 60. Apparently Web Extensions are in the works too.
Transitioning to a native client is painful at first, but it's worth it.
GMail's web interface is a piece of shit lately anyway.
What kind of emails need markdown composing?
And for formatting in general, the resulting email (composed in MailMate) will be very friendly to clients that prefer to display emails as plain text, since the text version is going to be very clean.
There's also a browser extension working with GMail's web interface too, but it doesn't work as well as MailMate: https://markdown-here.com/
However.... re-decentralization resonates quite well these days when it comes to the web. I wonder what it would take to be re-applies to email.
It's trivially easy to get blacklisted as spam that way...
I don’t know where this myth comes from that running your own mail infra means your mail will be marked as spam. You’re not the first (or second or third) person to mention it though.
Aside from Yahoo though, we generally haven't experienced any blacklisting or deliverability issues. It does require time to setup properly and maintain however, you can't just set it up and forget about it.
Can any random adversary easily have you blacklisted just for fun?
Can some Wordpress or other such service you run with your own email get you in trouble?
What about any when viruses (and botnets) in any PCs you have in your company go bezerk with your account?
And so on...
Sure, it's 'easy' to get around, by throwing more money and complexity at the problem, but it isn't some made up tale.
Granted you can't set up your own Google Mail domain for free today like you once could, but some of us are grandfathered in... I am, and I'm still looking at this as a better alternative to Gmail because even though it is Gmail, I can take my address with me if I do ultimately change my mind about Gmail.
(That's the first step, at least. You can never take @gmail.com with you, but if you want to start moving away, you could forward to your own domain and start thinking about where you would host it.)
I've been running my mail server for 10 years now, I got on blacklists 2 times: once due to a worm that got in through PHP, the other was a client's laptop that got a virus and used outlook express to send mail.
So how's that an argument that "it's fine"? Sounds like 2 times more than a regular person would want to deal with such issues within a decade, much less a small company. And it can take long to clear those things out if you're small fish...
If you're going to the hassle of actually switching, at lest don't do it from one big corp to the next.
Personally I use https://www.webfaction.com and am very happy with it. Also heard good things about FastMail, but Australia has some crazy laws coming so not sure about that. ProtonMail seems solid as well.