I see, the OS installs it and I don’t have to do anything else after installation. I understand now what most people with Nvidia have to go through if they are forced to use a specific distro. I just assumed that most distros will handle that as well for the user.
I have tried kmail, Geary, mailspring before I landed on betterbird. I’m not sure what you mean with slow, but it works without issues on my pc. It does a lot of stuff, but it’s a fork of Thunderbird, which you want to exclude based on the initial thread. There are not a lot of linux clients even worth trying. Good luck finding your jam.