Yeah I think you make some really good observations!
The 991 feels like many years of refinement when the 911 got a little more curvy in the late '90s and early 2000s. It started with the 996. I think that's when they introduced the splits that created three openings in the front bumper. The headlights were terrible, making this probably the worst looking 911. Notice that the headlights started to encroach into the bumper. I have an observation about this later.
I can see the 996 DNA in the 991. Large bumper splits. Thankfully they've ditched those awful headlight shape, but the headlights do clearly sit in between the fender and bumper.
For the 992, I think the designers looked back to the '80s and early '90s. Here are the 964 and the 993:
I see some similarities with the 992. The obvious one from the older 964 is the straighter bumper line. I also see a wide "open mouth" without splits on both below the license plates. Also notice the offset hood and bumper lines on the 993. Seems familiar!
One thing that really stands out to me: the headlights clearly sit inside of the fender space. It really feels like the designer tried to maintain that with the 992.