logging verbosity

[Fourhundred Thecat]

Hello,

I get lots of these messages in the log:

   dovecot:  imap-login: Login: user at 1.2.3.4, TLSv1.3 with ..
   dovecot:  imap(user)<10889><glzsCIi6AMbUGQtL>: Disconnected for
inactivity ...
   dovecot:  imap(user)<10887><vzjQB4i6/MXUGQtL>: Logged out ...

when user clicks on folder in Thunderbird, or sometimes even when the
Thunderbird window is in focus (without clicking anything).

Anyway, how can I suppress these info messages, while keeping the
important ones, such as auth problems?

I am using Dovecot v2.3.4.1 with 10-logging.conf with default values. I
see there is this line:

   # Log unsuccessful authentication attempts and the reasons why they
failed.
   auth_verbose = yes

I definitely want to keep logging unsuccessful auth, but how can I
suppress the verbose rest?

and lastly, can these settings be set per-user?

Can I suppress verbose for user 'bob' but keep for others?

thanks,