Unfocused terminal font brightness unintuitive with dark on white

[awisse]

Is your feature request related to a problem? Please describe.
I try to use the Unfocused terminal font brightness: setting in the General preferences tab with a dark green on white profile. This leads unfocused terminals to have higher contrast than the focused terminal.

Describe the solution you'd like
It would be nice to replace Unfocused terminal font brightness with a setting that dilutes/mixes the foreground (text) color with the background color instead so as to reduce the contrast compared to the focused terminal.

Describe alternatives you've considered
I might try to dig a little into the code to see whether there is anything I can do with CSS. Will report back.

Additional context