With Gmail, the unread email counter is taking into account the emails from the “All Mail”. The problem is that I often quickly delete/archive emails without reading them, so the mail disappears from the Inbox but stays unread in “All mail”.
How can I avoid this from happening? I want to exclude “All mail” from the counter.
Seems like the issue is as you said “I often quickly delete/archive emails without reading them”.
I can only suggest not to quickly delete them without reading emails first to avoid that happening, unless you really need to delete them straight away.
You can set in eM Client settings to read mail after X amount of seconds, so maybe suggest to set read mail to the min time eg: 1sec so it reads fast which may avoid showing unread in All Mail.
So if you don’t del mail before 1sec should be ok.