As long as it is the correct voltage and physical size, it doesn't matter. The higher the capacity, the longer uninterrupted run time. Charging the batteries outside the radio would be a must due to either longer charge time or higher charge current.
I'm having pretty good luck with the Amazon Basics AA NiMH rechargeables in my '325P2. I also have used Eneloops and they are pretty good performers but my set is losing capacity after several years of continuous use, so i decided to see how the Amazon Basics do.
I seem to get less life out of rechargeables in that scanner than my BCD396XT.
People have reported mixed results with Amazon Basics. I sent mine back, they all eventually failed too young. The real maker may change as the contract is re-placed each year, so there's no telling if what you got, is what you'll get.
OTOH Eneloop is always from the same source, more reliably.
I also have had good success with Amazon Basics in the high capacity model. I find over the past couple years that they have acted exactly like Eneloop. So similar, in fact, that I think they might be, with a different name. However, I also believe that there are likely more than one supplier an what you get might not work as well. I bought a dozen or so of them 2 years ago along with the same number of Eneloop batteries. All are still in service.