I suspect you need to go read Project Drawdown again. #1 is replacing high-GWP refrigerants, especially many of the HFCs that replaced CFCs, with low-GWP refrigerants, both HFOs and low-GWP HFCs (they aren't all the same). They aren't calling for eliminating air conditioning.

As heat increases, more buildings need cooling in the summer months for human comfort and survivability. Air conditioning will expand in use, but it will be low-GWP heat pumps, which incidentally use less electricity for the same cooling as standard air con.

The duck curve has little to do with building efficiency. That's a bit of a red herring. I suspect you meant it metaphorically, and were merely sloppy.

Efficiency becomes something necessary for other considerations, not for global warming avoidance. It's a business case question less than a mitigation concern.

That you think this will make building designers lazy is fascinating, but incorrect, based on the numerous experts in the space I've spoken to about embodied carbon and HVAC.