I don't think I've seen variable speed fans and compressors mentioned. If the thermostat can learn the heat loss/gain it can let the compressor/fan spool down to use less electricity occasionally. Also not all motors are at peak efficiency while they're at peak speed, so slowing it down can reduce electricity usage more than it reduces heat transfer.

Eta: variable speed can also prevent cycling where the air conditioner runs full blast for 5 minutes an hour because it's oversized or not hot enough outside.

Micro channel vs tube and fin coils is another area for you to look into in terms of build differences.

Then you get your indoor coil shapes, A coil vs N coil. You got your pistons vs thermo static valve (txv)

there is a lot of areas in the equipment and accompanying equipment that will throw those efficiencies out the window..

You should check out the Youtube channel "technology connections". They have videos that go into detail about heat-pumps. Specifically what the efficiency ratings mean, and how different units compare.

For portable air conditioners, many inexpensive units have only a single hose (hot air exhaust) rather than a dual hose (outside air intake and hot air exhaust) which is going to cause inefficiency (like, you're going to be pulling air from outside into the house by creating a pressure difference).

In addition to advances in fin design and compressor and motor efficiency and materials, there's also the option to use things like heat pumps instead of traditional compressor based ac systems. They tend to be more efficient or for the same size to produce more cold air for the same electricity.

Due to the fact that a heat pump moves heat and it is not a unidirectional process like a traditional compressor system is, heat pump air conditioning systems can be both heaters and coolers at about the same electrical efficiency.