When a default font is set in Options, use it for new text etc in Layouts.
Setting:

New Service Layer text inserted:

EDIT:
Expand the default graphics text style to show its font and properties to make it easier to see what Pro will use by default:

Edit 2:
When a default font is set, use it globally, including in new legends, etc.
Having to go into all sorts of styles and places to do the same thing over & over is inefficient.