Select a theme for each widget

I want to change the colors of some widgets to be different of the others. Each widget could have its own theme chooser and include also the size of the icon and text inside

Since 26.0 release, it is possible to assign custom active color for a widget, does that accomplish the first point?

I already use that feature. It is useful.
But I would like to be able to change the background color and font size of each widget individually.

I’d like some widgets without a border, that would be possible with individual themes for each widget.

I think this kind of customization would mean dashboards will easily become inconsistent so from a design perspective I’d probably discourage this.