97 Grand Cherokee Laredo 5.2 battery will drain if I don't unhook the negative
cable when not running
You have a parasitic drain. Lots of videos online about it. Simple to locate maybe a little tougher to fix based on circuit it is associated with.
Your alternator is drain your battery or battery cell crossed over. Test them individually. With a mulit reader your battery should read approx 12.5 with engine off and 15-16.5volts with engine running. Then alternator should be putting out 13-15 volts whilst running.