Alternator question on amp readings for charging

i had what was i thought was a good battery slightly at 4 years old. It went completely dead, and wouldn’t take a charge, only emergency start with my charger would car crank. Rather than loose another battery Im doing the alternator. My question is without a load, and with a load, what is the correct amp reading.
I may not have an alternator problem, just lost the battery 15 days of 90 + degrees in Atlanta . It reads at
13.25 without a load, which i know with a load thats borderline. I know over 14 is getting to high.
Ive just never lost a battery like that after driving 4 hours on a trip.

I’d suggest you try getting your battery load tested. One way a battery can fail is carry a charge but not carry a load.