How accurate is the battery tester at Autozone and O’reilly’s?

My girlfriend has a 2022 Subaru Outback. She’s been forgetting to turn her light off in her car and then a week later her car doesn’t start so I give it a jump and it starts up. Take the battery out today and go to Autozone to have it tested and the guy tells me it’s 100%. So I take the battery to O’reilly’s and they tell me it’s bad (just to compare). So I take it back to autozone to ask if they can charge it because O’reilly’s is saying it’s bad but they start giving me pushback to charge it. So I ask if they can just charge it for me if it’s free and give me that piece of mind. Got the battery back about an hour later and took it back to O’reilly’s to test it and they said it’s still bad (the two buildings are less then a mile apart btw)…now I’m a little annoyed wondering if it’s actually bad like what O’reilly’s is saying. I’m starting to hate autozone btw. Always trash service every time I go in.