I have been using K9 for a long time on Android. No complaints. I guess most Apple users will simply use the default email client, which works well and is probably better integrated and has a better UI than Thunderbird.
On Linux desktop, Thunderbird is still the best all around email/CardDAV/CalDAV client it seems, despite being unreasonably heavy.
Do most Apple users not just use the Gmail apps and web app? I haven't set up an email client in 20 years
From what I've heard though, Mail has pretty horrible searching in Apple land. Just for that, it may be worth it to look at alternatives.
K9 and Thunderbird on Android suck. The ui is clunky but worst of all, the search is bad. Very bad.
If you don’t do anything special, that will be enough but for everyone else that won’t do it.
If I type ‘repor’ in Apple mail, It will show me all report before I even type enter. And if there is too much, I will then add ‘2026’ for instance.
On k9, first you got to type the entire word because it won’t progressively search as you type, but then you press enter and see hundreds of mail so you want to add 2026 ? Too bad. Got to type report once again followed by 2026. Made a typo mistake ? Got to rewrite it all over again.
This is just bad.
And I’m not trying to diminish the work done by Thunderbirds/k9 developer, it’s just that it’s done by unpaid developers and it shows. Things move slowly and just suck at using.