For your first question, you cannot change the default of that dropdown for new objects. The default is applied based on the field itself. However, if you use an object that is NOT a field object (like a text box), it will default to the formula since it doesn't have context to a field.
You can always copy and paste another field that has conditional formatting applied instead of always drawing a new field.
For your second question, You can copy and paste from the calculation box itself, however you will still need to toggle the dropdown.
If the values need universal formatting applied throughout the database, have you thought about formatting the contents themselves rather than applying conditional formatting.
For Example, an auto-enter calculation on your "priority" field of:
self = "High" ; TextColor( self ; RGB(255,0,0) ) ;
self = "Medium" ; TextColor( self ; RGB(255,255,0) ) ;
self = "Low" ; TextColor( self ; RGB(0,255,0) ) ;
would automatically color the field contents in the database (unless field object or conditional formatting styles override it) as rich text. This may be a better route for you though than trying to style objects across hundreds of layouts.
I will try the auto-calculation as you suggested. As for the copy and paste as you suggested, at least it is one less step.
I know in other programs you can set it up to automatically have presets, but this is maybe a personal wish-list of mine that someday they would change.
Conditional formatting can’t be preset due to its ability to be context-free. In this case you can treat copy and paste as a preset by keeping a “template” object over in the hidden area to the right of the layout that you copy and paste as needed.