Yeah essentials is the low tier business plan

I am using proton essentials plan it gets you ten custom emails that you can use with three custom domains.

So I use one email for my game servers so those services use that then I have another general use email for sending info like recently added plex content or alerts from my server then a few mix and match for random stuff.

Not the cheapest but now I’m also using their calendar which is nice. I don’t use any desktop clients though I prefer to keep as much stuff in the browser

So just stick with firefox?