I’ve long been in agreement that functioning labels need to go but I’m not sure about replacing them with internalized versus externalized presentations. Autistic presentation can be as variable as autistic functioning; this would seem to replace one inconsistent, incommunicative phrase with another.
My priority is for a framing around support needs.
This, too, can be variable but seems to me far easier to generalize across a lifespan—or, at least, across life stages—than either functioning or presentation. Noting differences in presentation certainly communicates that autism isn’t WYSIWYG but someone with an internalized autism presentation still might have significant support needs, and vice versa.
In the real world—or, at least in my real world—the crux of how my life is going to be in the coming decades is entirely about my needed levels and kinds of support, irrespective of functionality or presentation at any particular moment.