have been using FairEmail and it works really well. I have to admit it is a very verbose client which offers a vers large number of options and settings even as you just want to send an email (there’s a popup with how you want to send it) but it has never failed me and has a very good support for updates and guide for setting it up. It’s free but if you like it I highly recommend to support the developer who is fully committed to it (not personally related to the project in any way). I would be very upset if this project were to die and I had to find another client.

Edit: link https://github.com/M66B/FairEmail