With that you probably mean these settings:
Those settings are only for newly created items, such as manually adding texts to the PCB.
Footprints that come from external libraries have pre-existing text sizes set in their own properties.
So it seems very unlikely to me tere would be a setting for this, but the “Edit Text and Graphics Properties” dialog is quite powerful and quick to use.
What you can do is create and manage your own footprint libraries and then set the text sizes to what you want.
It’s probably not very difficult to write a script and set all the text sizes in all library footprints to some pre-defined sizes, but you have to get past your OS’s read-only attribute, and re-run the script after each update of the libraries from KiCad itself, so it’s a quite dirty hack.