I'll be the contrarian and throw out there that if all you're looking for is e-mail, and you are already using a Gmail account (as but one example), the webmail interfaces are accessible. There are a number of members here who've mentioned that this is what they use.
Most of the major webmail interfaces allow you to add additional accounts that are not "their brand," too.
Webmail interfaces seldom undergo radical makeovers, and the small changes that do occur over time are generally easy to adjust to.
Thunderbird is an excellent email client. The last several versions of eM Client have been getting more and more accessible, and they take feedback from screen reader users seriously.
Brian - Windows 10 Pro, 64-Bit, Version 20H2, Build 19042
There are many who labor under the gross misapprehension that the Constitution is a cage and a laundry-list rather than a framework upon which great things have been and still will be built. Many things that are entirely Constitutional are not "in the Constitution," but are allowed under it.