There will be loss in the process so you should go a little above. You also need to account for the efficiency curve of your power supply: is it best efficient at 80% load? 90% load? Can it handle 120% momentarily in case of a spike?

CV power supplies are the standard: constant voltage. It outputs say 12V, and trips when overcurrent. A CC supply would limit current to say, 20A. It does so by dynamically adjusting the voltage output to match that target. That’s a lot less common and usually used for battery charging or testing/troubleshooting. So, I guess, don’t plug it on a battery charger.

It should come with specs as to what input it can take. Follow the recommendations. If it says DC give it DC unless you’re absolutely sure of the circuit in there. The presence of a rectifier and caps doesn’t tell you much given it’s an amplifier, it could be part of the amp circuit for the MOSFETs and not its power supply.