I would love to see another field, namely a checkbox field, so automatically letting Enpass check a checkbox when logging on.

Or unchecking a checkbox, for instance, to disable an option like 'keep me logged on', as several websites automatically check such a checkbox, which I don't like, because for easily logging on I am using a password manager, so such a checkbox makes it less secure, even if it's my own, non-shared computer.

I second this request!  I think more mature password managers tend to have this feature.

Curiously, when I imported my passwords from 1Password, which supports this feature, a lot of checkmark unicode characters came through, but obviously aren't functional.  Take a look at one of my logins: