1. Get a Class D amp.
2. Find some Kappa 9’s.
3. Set the the switch in the rear to Extended.
4. Crank up the music.
5. The Class D amp that doesn’t shut down will drive a 2 ohm load.
I can say this after completion of the above five steps,
This is gonna be one very short list of Class D amps
Crude way, but effective.
Better to just see how they behave in tests not understated into 8,4, and 2ohm and see if they can do "close" to the doubling act for each halving of the impedance.
My answer to the posted question,
Stay away from Class D amps to drive low impedance speakers.
Many manufacturers just under specify the 8ohm rating to allow their product to be in spec for the lower loads.
Yes this must be observed, as many "cheat" by understanding the 8ohm or the 4ohm watts, just so the 2ohm look better.
If all above is not taken on board, just buy a 3000!watt Class-D for just $400 and see how you go. https://www.storedj.com.au/behringer-nx3000-ultra-lightweight-3000w-class-d-power-amplifier